Health Central Experience Treating STEMI in an ULMCA Without On-Site Cardiac Surgery

Introduction

Emergent percutaneous coronary intervention (PCI) has been shown in numerous studies to provide better outcomes, including lower mortality, compared to thrombolysis for patients experiencing ST-segment elevation myocardial infarction (STEMI). Although there are exceptions, primary angioplasty is generally the treatment of choice in STEMI when logistical considerations allow an intervention to be performed in a timely fashion, with a desired door-to-balloon time of less than 90 minutes. PCI is also indicated in patients with cardiogenic shock following acute MI. In these patients, if timely surgery is impossible in an emergency, PCI and mechanical support are considered the first option for treatment.^1,2

However, in patients with significant left main coronary artery (LMCA) disease, current guidelines recommend coronary artery bypass grafting (CABG) as the treatment of choice and standard of care for revascularization. Patients presenting with STEMI due to left main coronary occlusion therefore present a dilemma, particularly when an experienced surgical team cannot quickly perform emergent bypass surgery. In centers offering elective CABG surgery, mobilizing the operating room team to perform CABG quickly enough to provide satisfactory myocardial salvage is challenging; in centers requiring transfer to another hospital for CABG, the challenge is nearly insurmountable. 

Revascularization strategy for patients with unprotected left main coronary artery (ULMCA) disease, especially in the setting of acute coronary syndrome (ACS) and STEMI, is the subject of ongoing debate. However, due to advances in PCI techniques, support devices, and adjunctive pharmacologic therapy, PCI with stenting has emerged as a feasible and life-saving revascularization treatment for these patients. In many institutions, PCI has become the most common strategy of revascularization in ACS patients with ULMCA disease. PCI is generally preferred in patients with multiple co-morbidities and in very sick patients with unstable hemodynamics and/or cardiac rhythm. In institutions such as ours, i.e., hospitals without on-site cardiac surgery, PCI in the setting of STEMI due to ULMCA disease often offers the only reasonable chance for survival. 

Case report

A 79-year-old white female with no prior history of coronary artery disease (CAD) presented to the cardiac catheterization laboratory with forty-five minutes of severe mid sternal chest pain, described as heavy pressure that did not radiate. She was diaphoretic and had marked dyspnea. She denied nausea, vomiting or syncope, and experienced no relief from sublingual nitroglycerin. Her past medical history was pertinent for hypertension, dyslipidemia, and remote tobacco abuse. An electrocardiogram (ECG) was consistent with acute anterolateral wall myocardial infarction, with ST elevation in leads I, aVL and V2-6, and reciprocal ST depressions in leads II, III and aVF (Figure 1).  

A “Code STEMI” was initiated based on the EMS ECG transmission. The patient was treated with 325 mg aspirin and 0.4 mg sublingual times 3 nitroglycerin per Orange County EMS medical treatment protocols. Upon arrival in the emergency department, she was quickly transported to the cath lab for cardiac catheterization and possible PCI. 

Upon arrival to the cath lab, the patient was awake and alert, but severely hypotensive. A 7 French (Fr) 11 cm Pinnacle sheath (Terumo) was placed in the right femoral artery using a modified Seldinger technique, but there was difficulty advancing a standard J-wire through the right iliac artery. This was accomplished after exchanging the wire for a stiff-angled Glidewire (Terumo). Right iliac angiography showed a 90% ostial stenosis. Coronary angiography demonstrated an 80% left main coronary artery (LMCA) stenosis, as well as a 95% ostial stenosis of the left anterior descending (LAD) (Figure 2). An extensive diagonal branch was free of disease. The left circumflex artery also had an ostial 90% stenosis, as well as a 75% proximal stenosis. A bifurcating first obtuse marginal (OM) branch had a 90% ostial stenosis of a large inferior branch of the OM (Figure 3). The right coronary artery (RCA) had only mild luminal irregularities, including both the posterior descending artery (PDA) and posterolateral branches (PLB), but none were significant. Left ventricular angiography revealed an ejection fraction of 30% due to extensive akinesis of the entire anterior wall, anterolateral wall, and apex. 

Emergent transfer to a larger, tertiary care medical center for emergent CABG was considered. However, after extensive discussion with the on-call cardiac surgeon, it was decided to proceed with PCI, particularly since the patient was rapidly deteriorating clinically; once the decision was made to proceed with PCI, angiography revealed the LAD had actually occluded. The patient was severely hemodynamically unstable and experienced cardiac arrest requiring cardiopulmonary resuscitation, atropine, epinephrine, calcium chloride and sodium bicarbonate intravenous (IV), use of inotropes and vasopressors, including dopamine HCl 800 mg / 500 mL D5W @ 15mcg/kg/min and norepinephrine 4mg / 250ml NaCl @ 0.3 mcg/kg/min IV, titrated for blood pressure support. The patient was intubated in the cath lab for respiratory support. 

At this point, IV bivalirudin was started and a 7 Fr XB 3.5 guide catheter (Cordis) was advanced to the left main ostium from the right femoral approach. A 0.014-inch 180 cm Asahi Prowater wire (Abbott Vascular) was advanced through the nearly occluded LMCA and down the now totally occluded LAD. A second 0.014-inch 180 cm Prowater wire was advanced into the circumflex artery (Figure 4). Balloon angioplasty of the distal LMCA and ostial LAD was performed using a 2.5 mm x 20 mm Apex Monorail PTCA dilatation balloon catheter (Boston Scientific) (Figure 5). A Resolute Integrity 3.5 mm x 15 mm (Medtronic) drug-eluting stent was deployed at the distal LMCA with extension into the LAD. TIMI grade 3 flow was restored with zero percent residual stenosis. 

A high-grade ostial stenosis of the circumflex artery was noted, presumably due to plaque shift and perhaps thrombus as well (Figure 6). Balloon angioplasty of the ostial circumflex was performed using a 3.0 mm x 15 mm Apex Monorail PTCA dilatation balloon catheter advanced through the struts of the LMCA/LAD stent. A Resolute Integrity 3.0 mm x 15 mm drug-eluting stent was deployed through the stent struts into the left circumflex artery, covering both the ostial and proximal stenosis. A kissing balloon technique was utilized (Figure 7). Zero percent residual stenosis with brisk TIMI-3 flow resulted (Figure 8). There was no compromise of the LMCA/LAD stent (Figure 9).

Due to the extensive infarct size and ongoing hemodynamic instability, the decision was made to place an intra-aortic balloon pump (IABP). The right iliac artery had an ostial 90% stenosis. Placing the balloon pump across this stenosis likely would result in acute right lower extremity ischemia. The 90% right iliac stenosis was dilated with a 5 mm x 80 mm Admiral Xtreme angioplasty balloon (Medtronic) and then stented at the ostium using a 6 mm x 40 mm Assurant cobalt chromium balloon-expandable stent (Medtronic). A CS100 IABP with IntelliSync (Marquet) was inserted without difficulty and without evidence of any compromise of the right lower extremity circulation. (An Impella left ventricular assist device [Abiomed], especially the 4.0 L/min device, would have been strongly indicated, but was not yet available at Health Central at the time of this procedure [although it is now available]).

Continued use of the right femoral access versus obtaining left femoral access was debated. If complex iliac disease had been present in the right iliac, it would have been an easier choice to access the left femoral artery and place the IABP via that approach, assuming similar disease on the left side was not present. However, it seemed far simpler to perform a quick percutaneous transluminal angioplasty and stent of the focal iliac stenosis of the right iliac artery, allowing use of the current access site without the small but definite risk of a left groin complication after obtaining access in a fully anticoagulated patient. Should the IABP have been required during the intervention rather than after, attempted utilization of the left iliac artery would have occurred. (Of note, this procedure was performed in a dual-purpose coronary/peripheral cath lab. Such an intervention in a coronary-only cath lab might be a less attractive option.)

Immediately after the procedure, the patient improved hemodynamically and stabilized, permitting transfer to a tertiary care facility. Arrangements were made for urgent transfer to our affiliate hospital, Orlando Regional Medical Center (ORMC), an 808-bed tertiary hospital in Orlando, Florida, and one of the state’s six major teaching hospitals, to exchange the IABP for a left ventricular assist device (LVAD). Our patient received an Impella 4.0 device support following transfer. Her final left ventricular ejection fraction was 50% by echocardiography. The patient was subsequently discharged home five days later, without angina or heart failure. 

Discussion

ULMCA disease in patients with ACS is a medical emergency with a very high in-hospital mortality rate, especially in those presenting with STEMI and/or hemodynamic or arrhythmic instability. Patients who have a LMCA stenosis are at increased risk of complications during or shortly after cardiac catheterization. Although PCI has been performed on unprotected LMCA stenoses, surgery is the preferred treatment and improves the likelihood of survival, as shown by the Coronary Artery Surgery Study (CASS) and the Veterans Administration Cooperative Study.³ More recent data from the SYNTAX trial suggests that elective stenting of left main coronary disease may be appropriate and reasonable in certain angiographic subsets of patients.⁴  

Cardiogenic shock carries very poor prognosis compared with less severe presentations of ACS. Despite hazards of increased mortality and morbidity, therapies that in less severely ill patients may only marginally improve outcomes can result in significant improvements in this high-risk subgroup. Yet despite advances in acute cardiovascular therapy, progress has been slow. The SHOCK trial showed the importance of revascularization to improve outcomes, but the recent IABP-SHOCK II trial failed to show any marginal benefit to adding hemodynamic support with IABP in the setting of shock, running counter to conventional wisdom.^5,6 Strategies to improve outcomes in these patients may rely more on application of proven therapies, such as primary PCI, and/or improving the safety of existing treatments, rather than relying on novel devices or drugs. 

In the Global Registry of Acute Coronary Events (GRACE), which included patients presenting between 2000 and 2007 with ACS and left main disease, a trend towards more PCI and less CABG was observed.⁷ Overall in-hospital mortality was 7.7%, but reached 11% in patients who presented with STEMI or left bundle brunch block (LBBB) and was as high as 34% in patients with cardiogenic shock or cardiac arrest.⁸ A complete occlusion of the left main is nearly always associated with cardiogenic shock and therefore represents a very high-risk situation requiring immediate life support strategies and urgent revascularization, often in conjunction with the use of an LVAD.^4,9

In a recent published meta-analysis of randomized patients with unprotected left main stenosis, the risk of death and myocardial infarction was comparable between CABG and PCI. However, patients undergoing CABG had a higher risk of stroke, whereas patients undergoing PCI were at a higher risk for repeated revascularization.¹

As reported by the American Hospital Association (AHA) in 2001, only 1,176 out of 4,609 U.S. hospitals were capable of performing primary percutaneous coronary intervention (PCI), while 79% of the population lived within a 60-minute ground transport of these hospitals.¹⁰ By 2006, that number grew to 1,695 out of 4,673 hospitals, a relative increase of 44%; but access to the procedure only grew from 79.0% to 79.9% of the population, a relative increase of 1%.¹¹  

The importance of treating ULMCA disease in the setting of STEMI without surgical back up is readily apparent. Although there are at least 5,724 registered hospitals in the U.S. today, according to the AHA, less than 2,000 of those hospitals offer PCI (based on 2006 statistics), and an unknown number of PCI-capable hospitals do not have on-site cardiac surgery. This number may be growing as acceptance of PCI without on-site surgery is evaluated on a state-by-state level.¹³ Our institution, Health Central Hospital, a 171-bed acute care hospital without on-site cardiac surgery, may be representative of a setting in which many acute MIs are treated in the U.S. today.

Upon patient presentation, the original plan was to transfer the patient to a tertiary care center, placing an IABP prior to transfer. However, after discussion with cardiac surgery consultants, it was agreed that the patient’s chance for survival would be highest with emergent intervention. While placing a cardiac assist device prior to proceeding with such a high-risk intervention would have been ideal, in view of the acute closure of the LAD and the resulting cardiac arrest, restoring coronary flow was felt to be the highest priority with the best chance of stabilizing the patient. 

Prior to placing an IABP or LVAD, it is important to study the iliofemoral anatomy angiographically to ensure that device placement will not compromise the lower extremity circulation. In this case, angioplasty and stenting of a severe iliac stenosis allowed placement of the IABP via the already-accessed right common femoral artery. If peripheral vascular intervention is not possible, the contralateral iliac should be evaluated to see if that vessel has less obstructive disease and is more appropriate for placement of the support device. 

Acute cardiogenic shock after myocardial infarction remains an important therapeutic challenge, associated with high in-hospital mortality rates attributable to severely reduced cardiac output. LVADs are increasingly being used in high-risk coronary interventional procedures to provide hemodynamic support. The Impella is able to unload the left ventricle rapidly and effectively increase cardiac output considerably more than is possible with an IABP.^3,5,6,14,15 LVAD utilization is feasible and results in a reduction of lactate levels, suggesting improved organ perfusion. However, 30-day mortality remains high in these patients, which likely reflects the last-resort character of Impella 2.5-application in selected patients with a poor hemodynamic profile and a greater imminent risk of death.⁵ It is expected that the recently introduced 4.0 L/min Impella device will further improve outcomes in this high-risk patient population with cardiogenic shock. Our experience with the Impella system in patients with STEMI complicated by profound cardiogenic shock has been favorable and suggests improved long-term outcomes. 

Conclusion

Herein, we present a case of PCI in a 79-year-old female patient with ULMCA STEMI who presented in cardiogenic shock to our cardiac catheterization laboratory. A high-risk intervention was performed without cardiac surgical back up. The patient was hemodynamically unstable, consistent with cardiogenic shock, due to massive myocardial infarction. Coronary angiography revealed complex left main thrombosis with involvement of the bifurcation. Emergent primary angioplasty and stenting was performed with a good angiographic and clinical outcome. The patient received an IABP prior to transfer to a tertiary care facility where she underwent LVAD placement and was successfully discharged 5 days post procedure with no angina or heart failure.

Unprotected left main coronary artery disease in patients with ACS is an uncommon but clinically serious situation, with high in-hospital mortality, especially in those presenting with STEMI and hemodynamic instability or arrhythmia. PCI has become a more common strategy for emergent revascularization in ACS patients with ULMCA disease and may be the only feasible option in patients with multiple co-morbidities and/or in very unstable patients. Immediate PCI of an LMCA stenosis, together with implantation of an IABP or LVAD, can be a life-saving procedure and if surgery is not immediately available, should be performed without delay.

Author disclosure: Reynaldo M. Grullon, RN, BSN, reports no conflict of interest regarding the content herein. 

Physician disclosure: Dr. Weinstock reports no conflict of interest regarding the content herein. 

This article received a double-blind peer review from members of the Cath Lab Digest editorial board.

About the author. Reynaldo M. Grullon, BSN, RN, is a graduate from Niagara University, NY, a registered nurse with over 20 years of critical care, emergency room, and cardiac cath lab experience. He is author of more than 10 peer-review articles and a U.S. Army Nurse Corps veteran. Reynaldo was awarded the 2001 Office Nurse of the Year Award for Clinical Excellence by the American Association of Office Nurses (AAON) for innovative education and leadership in Office Nursing. He may be reached at reygrullon@gmail.com.

About the physician that performed the case. Dr. Barry S. Weinstock graduated from Yale School of Medicine in 1987. He completed his internal medicine training at the Hospital of the University of Pennsylvania in Philadelphia in 1990 followed by cardiology fellowship at Cedars-Sinai Medical Center in Los Angeles. Dr. Weinstock has participated in numerous clinical trials involving coronary intervention and treatment of acute myocardial infarction and lectures nationally on these topics. In addition to all aspects of interventional cardiology including structural heart disease, his special interests include interventional treatment of complex peripheral vascular disease. He may be reached at bweinstock@me.com.

References and recommended reading

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