There is limited data on the incidence and outcomes of ST-segment elevation myocardial infarction (STEMI) due to the left main coronary artery (LMCA) lesions. We aimed to examine the trends and outcomes of STEMI due to LMCA lesions. The Nationwide Readmissions Database was utilized to identify hospitalizations with LMCA STEMI between January 2016 and December 2022. The primary outcome was all-cause in-hospital mortality during index admission. Among 1,528,764 weighted hospitalizations with STEMI from 2016 to 2022, 4,885 (0.3%) were due to LMCA lesions, of which 2156 (44.1%) had cardiogenic shock (CS). The number of LMCA STEMI hospitalizations and the incidence of CS increased over time. Mechanical circulatory support was used in 78.8% of the patients with LMCA STEMI and CS, with intra-aortic balloon pump being the most common modality (63%). Impella utilization increased from 4.5% in Q1 2016 to 34% in Q4 2022. Revascularization was performed in 78.2% of cases, with percutaneous coronary intervention (PCI) being the most common revascularization modality (62.1%). Among those who had PCI, intravascular imaging (IVI) was used in 18.3%, with a significant increase from 9.6% in Q1 2016 to 26.3% in Q4 2022. All-cause in-hospital mortality was 25.5% and was significantly higher among CS patients (43.4% vs 11.4%, p < 0.001). In conclusion, the incidence of LMCA STEMI increased from 2016 to 2022 with nearly half of the patients developing CS. IVI use in LMCA PCI was low (18.3%) but increased over time. More than 1 in 4 patients with LMCA STEMI died during the index hospitalization.
Graphical Abstract
Among patients hospitalized with ST-segment elevation myocardial infarction (STEMI), left main coronary artery (LMCA) is the culprit vessel in a small percentage of patients. However, it is associated with higher morbidity and mortality, which is attributed to the higher incidence of cardiogenic shock (CS) from pump failure and lethal ventricular arrhythmias. , As patients with LMCA STEMI are traditionally excluded from major clinical trials, clinical practice guidelines do not provide recommendations on the best management strategy for patients with STEMI due to LMCA disease. ,, Contemporary data on the characteristics, management strategies, and outcomes of STEMI due to LMCA disease in the United States (US) are limited to single-center series. Additionally, there is a lack of data on the trends and outcomes of CS complicating STEMI due to LMCA disease. To better understand this knowledge gap, we conducted this comprehensive analysis utilizing the Nationwide Readmission Database (NRD) to provide real-world insights into the trends, management, and outcomes of STEMI due to LMCA culprit lesion.
Study Design and Methods
Data source
Data were extracted from the Nationwide Readmissions Database (NRD) from 2016 to 2022. The details regarding the NRD have been published elsewhere. , The NRD is a part of the Healthcare Cost and Utilization Project (HCUP). In 2022, the NRD contained data from approximately 32.9 million weighted discharges from 30 States. Each calendar year, the NRD contains diagnoses and procedure codes using the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD 10-CM), and procedure (ICD 10-PCS) codes. These codes were used to identify the baseline characteristics, procedures, and outcomes ( Supplementary Table 1 ). The NRD is a publicly available database with deidentified hospitalization records; therefore, this study was exempt from institutional review board approval.
Study population
All patients aged 18 years or older with any discharge diagnosis of STEMI due to LMCA culprit lesion from 2016 to 2022 were included. We stratified our cohort according to the presence or absence of CS ( Supplementary Table 1 ). Admissions with missing data on mortality were excluded. For the readmission analysis, we excluded those admitted in December (since the NRD does not cross the calendar year) and those who died during the index admission.
Outcomes
Our analysis aimed to describe the trends, management, and outcomes of STEMI due to LMCA culprit lesion. The primary outcome was all-cause in-hospital mortality during the index admission. Secondary outcomes included cardiac arrest, stroke, bleeding, and renal complications, length of stay (LOS), costs, and 30-day urgent readmission.
Statistical analysis
All analyses were conducted using the appropriate weighting, stratifying, and clustering samples following HCUP regulations. Continuous variables were summarized as medians and interquartile range (IQR) and compared with the Mann-Whitney U test. Categorical variables were displayed as numbers and percentages and compared with Pearson’s chi-square or Fisher’s exact tests, as appropriate. All P -values were 2-sided with a significance threshold <0.05.
Multivariable logistic regression analyses were used to determine the parameters associated with CS and 30-day urgent readmission. The model performance and potential collinearity were assessed. For CS regression model, discrimination was acceptable with an Area Under the Curve (AUC) of 0.68 (95% confidence intervals [CI], 0.66–0.70), and all predictors had Variance Inflation Factor (VIF) values <2, indicating no concerning multicollinearity. Similarly, for the urgent 30-day readmission regression model, the AUC was 0.65 (95% CI, 0.62–0.69), with all predictors showing VIF values < 2, again suggesting no significant multicollinearity. Linear regression was used for trend analysis. Statistical analyses were performed using IBM SPSS Statistics for Windows (version 29.0. Armonk, NY: IBM Corp).
Results
Among 1,528,764 weighted hospitalizations with STEMI from 2016 to 2022, we identified 4,885 (0.3%) weighted hospitalizations with STEMI due to LMCA culprit lesions, of which 2,156 (44.1%) had CS. The number of hospitalizations with LMCA STEMI increased from 126 in the first quarter (Q1) of 2016 to 222 in the fourth quarter (Q4) of 2022 (P-trend <0.001). Similarly, the incidence of CS in LMCA STEMI increased from 44 in Q1 2016–100 in Q4 2022 (P-trend = 0.03) (Central Illustration, 1A).
Baseline patient’s and hospitals’ characteristics
The median age of patients with LMCA STEMI was 67 years, and more than two-thirds were men. The most common comorbidities were known coronary artery disease (CAD) (80.3%), hypertension (76.9%), heart failure (49.1%), and diabetes mellitus (DM) (34.2%). Most patients were treated at large or teaching hospitals. Approximately 14% were transferred from other hospitals ( Table 1 ).
Table 1
Baseline characteristics of the study’s population
| Total ( n = 4885) | LMCA STEMI without CS ( n = 2729) | LMCA STEMI with CS ( n = 2156) | P-value | |
|---|---|---|---|---|
| Age | 67 (59–76) | 67 (58–76) | 67 (59–76) | 0.08 |
| Female | 1439 (29.4%) | 820 (30%) | 619 (28.7%) | 0.48 |
| Transferred from another hospital | 671 (13.7%) | 283 (10.4%) | 389 (18%) | <0.001 |
| Comorbidities | ||||
| Morbid obesity | 273 (5.6%) | 153 (5.6%) | 120 (5.6%) | 0.99 |
| Smokers | 1226 (25.1%) | 739 (27.1%) | 487 (22.6%) | 0.01 |
| Hypertension | 3758 (76.9%) | 2168 (79.4%) | 1590 (73.8%) | 0.001 |
| Diabetes mellitus | 1671 (34.2%) | 926 (33.9%) | 746 (34.6%) | 0.74 |
| Atrial fibrillation | 1244 (25.5%) | 566 (20.7%) | 678 (31.4%) | <0.001 |
| Heart failure | 2399 (49.1%) | 1019 (37.3%) | 1380 (64%) | <0.001 |
| CAD | 3921 (80.3%) | 2196 (80.5%) | 1725 (80%) | 0.78 |
| -Prior MI | 568 (11.6%) | 385 (14.1%) | 183 (8.5%) | <0.001 |
| -Prior PCI | 65 (1.3%) | 46 (1.7%) | 19 (0.9%) | 0.11 |
| -Prior CABG | 355 (7.3%) | 236 (8.7%) | 119 (5.5%) | 0.004 |
| -Known CTO | 281 (5.7%) | 154 (5.6%) | 127 (5.9%) | 0.77 |
| PAD | 485 (9.9%) | 268 (9.8%) | 217 (10.1%) | 0.86 |
| Carotid disease | 178 (3.6%) | 102 (3.7%) | 76 (3.5%) | 0.76 |
| Prior CVA | 386 (7.9%) | 229 (8.4%) | 157 (7.3%) | 0.34 |
| Chronic lung disease | 923 (18.9%) | 495 (18.1%) | 428 (19.8%) | 0.30 |
| CKD | 1039 (21.3%) | 531 (19.4%) | 508 (23.6%) | 0.02 |
| -ESRD | 193 (4%) | 93 (3.4%) | 100 (4.7%) | 0.17 |
| Hospital and payer | ||||
| Teaching hospital | 3956 (81%) | 2168 (79.4%) | 1788 (82.9%) | 0.02 |
| Large hospital | 3259 (66.7%) | 1777 (65.1%) | 1482 (68.7%) | 0.05 |
| Medicare | 2729 (55.9%) | 1485 (54.8%) | 1234 (57.3%) | 0.22 |
CABG = coronary artery bypass grafting; CAD = coronary artery disease; CKD = chronic kidney disease; CS = cardiogenic shock; CTO = chronic total occlusion; CVA = cerebrovascular accident; ESRD = end stage renal disease; LMCA = left main coronary artery; MI = myocardial infarction; PAD = peripheral arterial disease; PCI = percutaneous coronary intervention; STEMI = ST-segment elevation myocardial infarction.
When stratified according to the presence or absence of CS, CS patients were more likely to have heart failure (64% vs. 37.3%, p < 0. 001), atrial fibrillation (31.4% vs. 20.7%, p < 0. 001), and chronic kidney disease (CKD) (23.6% vs. 19.4%, p = 0.017). They were more likely to be transferred from other hospitals (18% vs. 10.4%, p < 0.001). Patients without CS were more likely to have prior myocardial infarction (MI) (14.1% vs. 8.5%, P < 0.001) and prior coronary artery bypass graft (CABG) surgery (8.7% vs. 5.5%, p = 0.004) ( Table 1 ).
Predictors of shock among patients with LMCA STEMI
On multivariable regression analysis, prior history of heart failure had the strongest association with CS (adjusted odds ratio [aOR] 3.04, 95% CI 2.54, 3.65, p < 0.001). The other factor that was associated with a higher risk of CS was atrial fibrillation. In contrast, prior MI (aOR 0.59, 95% CI 0.45–0.77, p < 0.001), prior CABG (aOR 0.60, 95% CI 0.42–0.85, p = 0.005) and hypertension (aOR 0.68, 95% CI 0.55-0.85, p < 0.001) were associated with a lower risk of CS. There was no association between age or sex and CS ( Supplementary Table 2 ).
In-hospital management of patients with LMCA STEMI
Mechanical circulatory support (MCS) was used in half of the patients with LMCA STEMI with intraaortic balloon pump (IABP) being the most common modality (68%), followed by Impella (37.8%). There was no change in overall MCS utilization during the study years; however, Impella utilization increased Fig. 1 .
Temporal trends in in-hospital mortality. Temporal trends in in-hospital mortality in hospitalizations with LMCA STEMI from January 2016 to December 2022. CS = cardiogenic shock; LMCA = left main coronary artery; MCS = mechanical circulatory support; STEMI = ST-segment elevation myocardial infarction.
Central Illustration: Panel 1 A. Temporal Trends in LMCA STEMI admissions from 2016 to 2022. B. Temporal Trends in MCS use in LMCA STEMI with CS. C. Temporal Trends of Intravascular Imaging use in LMCA STEMI patients undergoing PCI. Panel 2. Outcomes of LMCA STEMI. AKI = acute kidney injury; CS = cardiogenic shock; ICH = intracranial hemorrhage; LMCA = left main coronary artery; PCI = percutaneous coronary intervention; STEMI = ST-segment elevation myocardial infarction. AKI = acute kidney injury; CS = cardiogenic shock; ICH = intracranial hemorrhage; LMCA = left main coronary artery; PCI = percutaneous coronary intervention; STEMI = ST-segment elevation myocardial infarction
Among CS patients, MCS was used in 78.8% of cases without significant changes over time. However, there was a decline in IABP use (61.4% in Q1 2016 to 53% in Q4 2022, P-trend = 0.011) and an increase in Impella use (4.5% in Q1 2016 to 34% in Q4 2022, P-trend = 0.009). (Central Illustration, 1B) IABP utilization in patients with LMCA STEMI and CS was lower than in those without CS (63% vs. 79.2%, p < 0.001). Conversely, Impella utilization was higher in CS patients (44.7% vs. 22.5%, p < 0.001) ( Table 2 ).
Table 2
In-hospital management of hospitalizations with LMCA STEMI
| Total ( n = 4885) | LMCA STEMI without CS ( n = 2729) | LMCA STEMI with CS ( n = 2156) | P-value | |
|---|---|---|---|---|
| Mechanical ventilation | 1605 (32.9%) | 382 (14%) | 1223 (56.7%) | <0.001 |
| MCS * | 2463 (50.4%) | 763 (28%) | 1700 (78.8%) | <0.001 |
| IABP | 1675 (68%) | 605 (79.2%) | 1070 (63%) | <0.001 |
| Impella | 931 (37.8%) | 172 (22.5%) | 759 (44.7%) | <0.001 |
| ECMO | 276 (11.2%) | 40 (5.3%) | 236 (13.9%) | <0.001 |
| Revascularization | 3819 (78.2%) | 2067 (75.7%) | 1752 (81.3%) | <0.001 |
| PCI | 2370 (62.1%) | 1259 (60.9%) | 1111 (63.4%) | 0.29 |
| CABG | 1520 (39.8%) | 837 (40.5%) | 683 (39%) | 0.53 |
| PCI + CABG | 71 (1.9%) | 29 (1.4%) | 42 (2.4%) | 0.16 |
| Intravascular imaging | 433/2370 (18.3%) | 220/1259 (17.5%) | 213/1111 (19.2%) | 0.42 |
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