Acute total occlusion of the unprotected left main coronary artery (LMCA) is a dramatic event. There are limited data regarding this population. We aimed to describe the clinical presentation and outcomes of patients and to determine predictors of in-hospital mortality.
MethodsThis retrospective study included patients presenting with acute (<12 h) myocardial infarction due to total occlusion of the LMCA (TIMI flow 0) between January 2008 and December 2020 in three tertiary hospitals.
ResultsDuring this period, 11036 emergent coronary angiographies were performed, 59 (0.5%) of which revealed acute total occlusion of the LMCA. Patients’ mean age was 61.2 (SD±12.2) years and 73% were male. No patients had left dominance. At presentation, 73% were in cardiogenic shock, aborted cardiac arrest occurred in 27% and 97% underwent myocardial revascularization. Primary percutaneous coronary intervention was performed in 90% of cases and angiographic success was achieved in 56% of procedures, while 7% of patients underwent surgical revascularization. In-hospital mortality was 58%. Among survivors, 92% and 67% were alive after one and five years, respectively. After multivariate analysis, only cardiogenic shock and angiographic success were independent predictors of in-hospital mortality. Use of mechanical circulatory support and presence of well-developed collateral circulation were not predictive of short-term prognosis.
ConclusionAcute total occlusion of the LMCA is associated with a dismal prognosis. Cardiogenic shock and angiographic success play a major role in predicting the prognosis of these patients. The effect of mechanical circulatory support on patient prognosis remains to be determined.
A oclusão aguda total de um tronco comum desprotegido é um evento dramático. Há poucos dados na literatura relativos a esta população. Este trabalho pretende descrever a sua apresentação e outcomes, bem como determinar preditores de mortalidade intra-hospitalar.
MétodosEste estudo retrospetivo incluiu doentes com enfarte agudo do miocárdio (<12 h de evolução) por oclusão total do tronco comum (thrombolysis in myocardial infarction=0) entre janeiro de 2008 e dezembro de 2020 em três hospitais terciários.
ResultadosDurante este período foram realizadas 11 036 coronariografias emergentes. Dessas, 59 (0,5%) revelaram oclusão aguda do tronco comum. Os doentes tinham em média 61,2 (±12,2) anos e 73% eram homens. À apresentação, 73% encontravam-se em choque cardiogénico e 27% sofreram paragem cardíaca abortada. Nenhum apresentava dominância esquerda e 97% foram submetidos a revascularização. Em 90% foi feita intervenção coronária percutânea, atingindo-se critérios de sucesso angiográfico em 56% dos procedimentos, e 7% foram submetidos a revascularização cirúrgica. A mortalidade intra-hospitalar foi de 58%. Dos sobreviventes, 92% e 67% encontravam-se vivos após um e cinco anos de follow-up, respetivamente. Após análise multivariada, apenas a presença de choque cardiogénico e sucesso angiográfico foram preditores independentes de mortalidade intra-hospitalar. A utilização de suporte circulatório mecânico e a presença de circulação colateral desenvolvida não foram preditores de morte intra-hospitalar.
ConclusãoA oclusão aguda do tronco comum associa-se a um prognóstico catastrófico. A presença de choque cardiogénico e o sucesso angiográfico são fundamentais como preditores de prognóstico a curto prazo. O efeito do suporte circulatório mecânico no seu prognóstico permanece por esclarecer.
Acute total occlusion of the unprotected left main coronary artery (LMCA) is usually a catastrophic event with a dismal presentation. Owing to the amount of affected myocardium, it often leads to abrupt severe circulatory failure, malignant arrhythmias and sudden cardiac death. As such, these patients represent a group with very high risk of mortality.
There are limited and inconsistent data regarding this population, mostly confined to small observational studies, most of which also include patients with subtotal occlusion of the LMCA.1–7 Thus, clinical management of these patients represents a particular challenge.
The objectives of our study are to describe the clinical presentation and outcomes of patients with acute total occlusion of the LMCA and to determine predictors of in-hospital mortality in these patients.
MethodsWe performed a retrospective multicenter study that identified patients with ST-elevation myocardial infarction (STEMI) or high-risk non-ST-elevation myocardial infarction who underwent emergent coronary angiography between January 2008 and December 2020 in three tertiary hospitals. Among this cohort, patients with acute total occlusion of the LMCA (thrombolysis in myocardial infarction [TIMI] flow 0) were included in the study.
We excluded patients with subacute (>12 h) presentation, subtotal LMCA occlusion, previous LMCA angioplasty, previous coronary artery bypass grafting, or iatrogenic LMCA occlusion. Patients with acute aortic or coronary dissection or infective endocarditis were also excluded.
Data on demography, clinical features and outcome were collected from all in-hospital and clinical records.
In each center an interventional cardiologist was responsible for reviewing the coronary angiograms performed in their respective center. These investigators were blinded to all other patient data.
Variables assessed included the presence of cardiogenic shock at admission, defined as the presence of sustained hypotension (systolic blood pressure <90 mmHg lasting ≥30 min) or the need for support to maintain systolic blood pressure >90 mmHg, associated with signs of end-organ hypoperfusion including cool extremities, oliguria (<30 ml/h) and altered level of consciousness.8
Coronary collateral circulation was graded according to Rentrop's classification: grade 0, no filling of the occluded vessel; grade 1, filling of the side branches; grade 2, partial filling of the epicardial vessel; or grade 3, complete filling of the epicardial vessel.9
Angiographic success was defined as residual stenosis <30% with TIMI flow 3.
The study protocol conforms to the ethical guidelines of the 1975 Declaration of Helsinki as reflected in prior approval by the institution's human research committee.
Statistical analysisContinuous variables were expressed as means±standard deviation (SD) and/or medians with interquartile range (IQR) as appropriate. Discrete variables were expressed as numbers or percentages. Statistical comparisons were performed using the Student's t test or the Mann–Whitney test for continuous variables, and the chi-square test or Fisher's exact test for categorical variables, as appropriate. A p-value <0.05 was considered statistically significant.
Univariate logistic regression analysis was performed with in-hospital death as the dependent variable. Multivariate stepwise logistic regression analysis was performed in which independent variables were removed from the model if their p-value was >0.10.
All statistical analyses were performed using IBM SPSS software (version 25.0, IBM SPSS Inc., Chicago, IL).
ResultsIncidence and baseline clinical dataBetween January 2008 and December 2020, 11036 patients underwent emergent coronary angiography in the three participating centers. Acute total occlusion of the LMCA was identified in 59 (0.5%) of these cases. Baseline demographic and clinical characteristics of the study population are presented in Table 1. Patients’ mean age at the time of the event was 61.2 (SD±12.2) years and 43 (73%) were male. There was a relatively low prevalence of cardiovascular risk factors, and only five (9%) had a history of ischemic heart disease. Chest pain was reported in 54 (93%) clinical presentations. At hospital admission, 47 (81%) patients had ST-segment elevation on the ECG and 43 (73%) were in cardiogenic shock. Aborted cardiac arrest occurred in 16 (27%) patients prior to catheterization (of these, 37% were out-of-hospital and 63% were in-hospital cardiac arrests).
Baseline demographic and clinical characteristics of the study population (n=59).
| Age, years, mean±SD | 61.5±12.2 |
| Male, n (%) | 43 (72.9) |
| Cardiovascular risk factors, n (%) | |
| Hypertension | 27 (45.8) |
| Diabetes | 15 (25.4) |
| Dyslipidemia | 29 (49.2) |
| Smoking | 27 (45.8) |
| Obesity | 11 (18.6) |
| Ischemic heart disease, n (%) | 5 (8.5) |
| Peripheral artery disease, n (%) | 1 (1.7) |
| Stroke, n (%) | 4 (6.8) |
| Chronic kidney disease, n (%) | 3 (5.1) |
| Presentation, n (%) | |
| Chest pain | 54 (93.1) |
| STEMI or new LBBB | 47 (81.0) |
| Cardiogenic shock | 43 (72.9) |
| Cardiac arrest | 16 (27.1) |
| Symptom to balloon time, hours, mean±SD | 3.8 (2.7) |
LBBB: left bundle branch block; SD: standard deviation; STEMI: ST-elevation myocardial infarction.
Angiographic and procedural data are presented in Table 2. A femoral approach was used in the majority of procedures. Right dominance was present in all patients except one, who had co-dominancy. Thirty-four cases (58%) had significant coronary artery disease beyond the LMCA. In 29 (52%) cases, the occlusion was located in the distal segment of the LMCA at the level of the bifurcation. Data regarding collateral circulation were available in 54 patients. Of these, 44 (82%) had a Rentrop score <2. These patients had a significantly higher prevalence of cardiogenic shock compared to patients with Rentrop score ≥2 (79.5% vs. 40.0%, p=0.02).
Angiographic and procedural data (n=59).
| Radial access, n (%) | 12 (20.3) |
| Coronary dominance, n (%) | |
| Right | 58 (98.3) |
| Balanced | 1 (1.7) |
| Left | 0 (0.0) |
| Location of LMCA lesion, n (%) | |
| Ostial | 18 (32.1) |
| Midshaft | 9 (16.2) |
| Distal | 29 (51.7) |
| Disease extent, n (%) | |
| LMCA only | 24 (40.7) |
| LMCA+1 vessel | 11 (18.6) |
| LMCA+2 vessels | 17 (28.8) |
| LMCA+3 vessels | 6 (10.2) |
| Collateral circulation, Rentrop class, n (%)a | |
| 0 | 37 (68.5) |
| 1 | 7 (13.0) |
| 2 | 5 (9.3) |
| 3 | 5 (9.3) |
| Revascularization, n (%) | |
| PCI | 53 (89.8) |