Acute myocardial infarction due to left main coronary artery occlusion. Therapeutic strategy

Outcome of left main stem percutaneous coronary intervention in a UK nonsurgical center: A 5-year clinical experience

OBJECTIVES

To evaluate the outcome of unprotected left main stem (LMS) percutaneous coronary intervention (PCI) in a large UK nonsurgical center.

BACKGROUND

PCI on unprotected LMS is increasingly regarded as a viable alternative to coronary artery bypass grafting (CABG) with comparable outcome and safety profile in select groups. The safety and efficacy of unprotected LMS PCI without on-site surgical back up has not been reported.

METHODS

Data on all unprotected LMS PCI performed between January 2011 and December 2015, was collected from the local PCI database and electronic patient records. In hospital and 1-year major adverse cardiovascular events (MACE) (all-cause mortality, myocardial infarction [MI], stroke, and target vessel revascularization [TVR]) was recorded.

RESULTS

249 patients had unprotected LMS intervention during the study period. 77% of patients (n = 192) were male and mean age was 70 ± 12 years. 31% (n = 78) of cases were elective, 44% (n = 109) NSTEMI, and 25% (n = 62) STEMI. Anatomical distribution: 19% (n = 47) ostial left main, 31% (n = 77) shaft, and 50% (n = 125) bifurcation. The mean SYNTAX score was 24.4 ± 10.6. 22% (n = 55) of patients had severe LV impairment preprocedure and 13% (n = 33) were in cardiogenic shock at presentation. 35% (14%) required IABP support. The vast majority (98.4%) of procedures were successful. No patients required emergency transfer for CABG surgery. There were 25 (10%) in-hospital deaths. 68% of in-hospital deaths occurred in patients undergoing primary PCI for STEMI. 72% of patients who died were in cardiogenic shock at presentation. The 12-month MACE rate was 17.2%. Death occurred in 11.6%, MI in 2.4%, TVR in 2.4%, and stroke in 0.8% of patients.

CONCLUSION

These results highlight the safety and efficacy of unprotected LMS PCI in a high volume non-surgical center.

Real-time Pressure-volume Analysis of Acute Myocardial Infarction in Mice

Acute myocardial infarction can lead to acute heart failure and cardiogenic shock. The evaluation of hemodynamics is critical for the evaluation of any potential therapeutic approach directed against acute left ventricular (LV) dysfunction. Current imaging modalities (e.g., echocardiography and magnetic resonance imaging) have several limitations since data on LV pressure cannot directly be measured. LV catheterization in mice undergoing coronary artery occlusion could serve as a novel method for a real-time evaluation of LV function. At the beginning of the procedure, mice were anesthetized followed by endotracheal intubation. For LV catheterization, the right carotid artery was exposed via middle-neck incision. The catheter was introduced and placed into the LV cavity. Left thoracotomy was conducted and the left main coronary artery (LCA) was ligated. To induce reperfusion, the suture was released after 45 min. Pressure-volume data was recorded at all times. Ligation of the LCA caused a decrease in LV systolic function as evidenced by a 30% reduction in stroke volume, LV ejection fraction (EF), and cardiac output. Maximum dP/dt as a parameter for LV contractility was also significantly reduced and diastolic function was severely impaired (minimum dP/dt -40%). Reperfusion over a period of 20 min did not lead to a complete recovery of LV function. Real-time pressure-volume analysis served as a valid procedure for monitoring cardiac function during acute myocardial infarction in mice. Maintaining stable anesthesia and a standardized surgical approach was crucial to ensure valid results. As the early phase of acute myocardial infarction is critical for morbidity and mortality, the delineated method could be beneficial for preclinical evaluation of new strategies for cardioprotection.

Outcomes following primary percutaneous coronary intervention for unprotected left main-related ST-segment elevation myocardial infarction

INTRODUCTION

Unprotected left main (ULM) related ST-segment elevation myocardial infarction (STEMI) is a severe event, often leading to circulatory failure and/or sudden cardiac death. Although high-risk ULM thrombosis populations treated by primary percutaneous coronary intervention (PPCI) have been previously described, very little is known regarding the outcomes following PPCI for ULM-related STEMI in a hospital without on-site surgical back-up.

METHODS

A retrospective cohort analysis was performed on all consecutive patients who underwent PPCI for ULM-related STEMI in a single center. The primary end-point was to assess in-hospital mortality in the overall population and according to the presence/absence of cardiogenic shock at admission.

RESULTS

Between October 2006 and December 2012, 1094 patients underwent PPCI for STEMI. PPCI for ULM-related STEMI was performed in 34 (3.1%) patients. Among these, 22 (64.7%) were in cardiogenic shock at admission. Baseline mean ejection fraction was lower (P = 0.008), whereas the prevalence of patients with pre-procedural cardiac arrest and Killip Class III-IV was significantly higher in the cardiogenic shock (P = 0.05 and P < 0.001, respectively) compared with non-cardiogenic shock group. Furthermore, patients with cardiogenic shock had a higher prevalence of pre-procedural thrombolysis in myocardial infarction flow 0-1 (P = 0.05) and associated other vessel chronic total occlusion (P = 0.05) compared with non-cardiogenic shock group. Procedural success rate was lower in the cardiogenic shock compared with non-cardiogenic shock group (77.3 vs. 100%, P = 0.09), whereas in-hospital mortality rate was significantly higher in the cardiogenic shock compared with non-cardiogenic shock group (36.4 vs. 0%, P = 0.02). No deaths were reported among survivors of the acute phase at mid-term follow-up, whereas target lesion revascularization rate was 7.6%.

CONCLUSIONS

PPCI for ULM-related STEMI in a hospital without on-site surgical back-up was technically feasible in most of the cases. Although the procedural success and in-hospital mortality rates were influenced by cardiogenic shock at admission, an excellent mid-term outcome among patients who survived the hospitalization was reported independently by the severity of clinical presentation.

The acutely occluded left main coronary artery culprit in cardiogenic shock and initial percutaneous coronary intervention: a substudy of the Manitoba “no option” left main PCI registry

We aim to describe the in-hospital outcomes of the first reported Canadian cohort of patients with cardiogenic shock and acute myocardial infarction (MI) due to acute and total occlusion of the left main coronary artery, treated with initial percutaneous coronary intervention (PCI). Acute left main thromboses with cardiogenic shock were identified (N = 8) from a retrospective consecutive cohort of high risk left main PCI (N = 56) performed at our institution from 2004–2009. The mean age was 62.3 ± 13.2 years, with 6 (75%) male patients. Successful PCI was performed in all patients, with thrombectomy utilized in 4 patients (50%), stenting in 7 patients (88%), and intra-aortic balloon pump augmentation in 7 patients (88%). Two patients (25%) required extracorporeal membrane oxygenation (ECMO) and 2 other patients required ventricular assist devices. Post-PCI coronary artery bypass grafting (CABG) was performed for 2 patients (25%). The mean SYNTAX score was 26.6 ± 10.5. The mean logistic EuroSCORE was 30.4 ± 12.6%. In-hospital mortality occurred in 3 patients (38%). Acute left main occlusion is a rare but devastating presentation of myocardial infarction, invariably with cardiogenic shock. Emergent PCI may be an effective method to acutely revascularize this subset of patients; however, aggressive post-PCI care including ECMO, CABG, and ventricular support may be required to improve patient survival.

Percutaneous coronary intervention of unprotected left main coronary artery disease as culprit lesion in patients with acute myocardial infarction

OBJECTIVES

This study sought to evaluate short- and long-term outcomes of patients undergoing emergency percutaneous coronary intervention (PCI) for acute myocardial infarction due to a culprit lesion in an unprotected left main coronary artery.

METHODS

In this retrospective, 2-center, international observational study, 5,261 patients were admitted between February 2005 and December 2008 with acute myocardial infarction and treated with PCI; of these, 1,277 were ST-segment elevation myocardial infarction and 3,984 non-ST-segment elevation myocardial infarction. We identified 48 patients among this cohort who underwent emergency PCI to an unprotected left main coronary artery culprit lesion.

RESULTS

Mean age was 70 ± 12.5 years, and 45% of the patients presented with ST-segment elevation myocardial infarction or new left bundle branch block. Cardiogenic shock was present in 45%, and distal left main coronary artery disease was present in 71% of patients. Angiographic procedural success was achieved in 92% of patients. Overall in-hospital mortality was 21%, due in all cases to refractory, multiorgan failure. Twenty-five percent experienced major adverse cardiac events, defined as death, myocardial infarction, stent thrombosis, and target vessel revascularization. In patients presenting in cardiogenic shock, in-hospital mortality was 32%. At 1-year follow-up, in-hospital survivors had a mortality rate of 10.5%, whereas 18.4% experienced subsequent major adverse cardiac events. Long-term prognosis was excellent in hospital survivors with a 1-year survival rate of 89.5%.

CONCLUSIONS

Patients with acute myocardial infarction and thrombosis of the unprotected left main coronary artery are a high-risk subgroup with a substantial mortality, particularly if they present in cardiogenic shock. We demonstrate that in these patients, PCI is a feasible treatment option associated with reasonably good outcomes. Long-term prognosis is excellent in hospital survivors with an 89.5% survival rate at 1 year.

Stenting for left main coronary artery occlusion in adolescent: A case report

Acute total or subtotal occlusion of left main coronary artery (LMCA) is a catastrophic and mostly fatal event. Patients may present with cardiogenic shock and die whenever this event occurs. Survival is strongly dependent on the presence of collateral blood flow to the left coronary artery or a dominant right coronary artery, and emergency intervention for preserving the left ventricular function. Here, we present a case of a 14-year-old boy with subtotal occlusion of the LMCA accompanying acute myocardial infarction probably caused by congenital syphilis according to his positive serum syphilis antibody. His survival was closely associated with a dominant right coronary artery and timely thrombolytic therapy. Finally, he was treated with angioplasty and paclitaxel-eluting stent implantation. He was followed up after stenting and was doing quite well at the time when we wrote this paper.

Percutaneous coronary intervention with stenting of left main coronary artery with drug-eluting stent in the setting of acute ST elevation myocardial infarction

AIM

Primary angioplasty of the left main coronary is not a common procedure. We present 16 cases of angioplasty of left main coronary artery with drug-eluting stent (DES) implantation in the setting of acute ST elevation myocardial infarction.

METHOD

Between December 2003 and November 2005, sixteen patients presented with acute ST elevation myocardial infarction where the left main coronary artery was shown to be involved with or without the left anterior descending or left circumflex arteries. Primary angioplasties were performed on the unprotected left main coronary artery. Five patients received direct stenting while the rest had pre-dilatation. Only one patient received Taxus(R) while the rest received Cypher(R) stents.

RESULTS

Of the sixteen patients, eleven developed cardiogenic shock necessitating intra-venous inotropic and intra-aortic balloon counter-pulsation support. Seven perished in hospital (46%); four within the first day while one had a complicated course and perished on the 42nd day of hospitalization. There was no difference in clinical history (hypertension, diabetes, age, and previous coronary intervention) or hemodynamic features (presenting blood pressure, duration of infarct, stent length, and maximum balloon size or pressure) between the two groups. However, the use of inotropes and intra-aortic balloon counter-pulsation (100% vs. 44% p=0.034) was significantly more common in the group which perished. Patient with cardiogenic shock had increased mortality of 63%. Of the nine survivors, one required repeat intervention for subacute stent thrombosis at sixteenth day and one underwent coronary bypass surgery at three months. All remained well up to mean follow up of 420 days.

CONCLUSION

Left main coronary artery infarct especially in the setting of cardiogenic shock has a very high mortality rate. Percutaneous intervention can be performed on these patients with minimal delay. In our series, we have shown that primary intervention of the unprotected left main coronary artery with a drug-eluting stent carries an acceptable level of major adverse coronary event. In those who survived the initial event, there is a low rate of mortality or morbidity.

Left main coronary artery thrombus: a case series with different outcomes

Left main coronary artery (LMCA) thrombosis with acute myocardial infarction is an uncommon condition with an extremely high mortality. The small number of reported cases prevents the development of an evidence-based approach. Hence there are no clear-cut guidelines describing the best management approach for this condition. We describe our experience with six patients who presented with LMCA thrombosis and discuss the epidemiology, etiology and management options available for this high-risk subgroup.

Use of an extracorporeal left ventricular assist system after acute myocardial infarction due to occlusion of the keft main coronary artery

A 35-year-old man presented to our institution one day after the onset of dyspnea. Coronary angiography revealed the occlusion of the left main trunk. The left main coronary artery and the left circumflex artery were recanalized, but he was hypotensive with low cardiac output. Even after he was placed on circulatory support with veno-arterial extracorporeal membrane oxygenation (ECMO), hemodynamic deterioration could not be reversed, and lung edema developed. The decision was made to use Toyobo LVAS. With institution of left ventricular assist system (LVAS), however, the patient's arterial saturation decreased. Peripheral veno-venous (V-V) ECMO was promptly established, and the patient's arterial saturation improved. On postoperative day 3, the patient was successfully weaned from V-V ECMO. He was extubated on postoperative day 28. The patient was recovered without any serious complications. Although echocardiography showed no substantial improvement in left ventricular function, his general condition is doing quite well with the assist of Toyobo LVAS. He is on rehabilitation program and awaiting heart transplantation.

Coronary stenting in an elderly patient with an acute myocardial infarction at left main trunk

Acute myocardial infarction (AMI) caused by an occlusion of the left main trunk (LMT) is a rare angiographic finding. The prognosis is usually extremely poor, particularly in an elderly patient, unless complete reperfusion is rapidly established. We experienced a survival case of an elderly man with AMI at the LMT. A 91-year-old man with cardiogenic shock was referred to our hospital for the treatment of AMI. Left ventriculograms showed that akinesis in the anterolateral and apical wall segments had resulted in an ejection fraction of 30.8%. Coronary angiograms revealed a 90% narrowing at the ostium of the LMT. Intravascular ultrasound images showed a circumferential calcification at the site of the minimum lumen diameter of the LMT. We successfully dilated this calcified narrowing using a coronary stent, and the patient was discharged without complications 1 month later. The patient was asymptomatic 6 months later.