Influence of Coronary Vessel Dominance and Outcome in STEMI
Influence of Coronary Vessel Dominance and Outcome in STEMI
The population consisted of consecutive patients presenting with first STEMI at the Leiden University Medical Center between 2004 and 2008. Patients with previous myocardial infarction, previous percutaneous coronary intervention (PCI), and/or previous coronary artery bypass grafting were excluded. The diagnosis of STEMI was defined based on criteria of typical chest pain, elevated cardiac enzyme levels, and typical changes on the electrocardiogram. All patients were treated according to the institutional MISSION! protocol, based upon the European Society of Cardiology and American College of Cardiology/American Heart Association guidelines. The protocol includes primary PCI, optimal medical therapy initiated early during hospitalization, and two-dimensional echocardiography performed within 48 h of admission to assess residual left ventricular function.
Demographic, clinical, angiographic, and echocardiographic data were prospectively collected in the departmental Cardiology Information System (EPD-Vision®, Leiden University Medical Center, Leiden, The Netherlands) and retrospectively analysed. Patients with uninterpretable coronary angiographic images for coronary vessel dominance were excluded from analysis.
Images of the coronary angiography and PCI were obtained using standardized angiographic projections according to the guidelines of the American College of Cardiology/American Heart Association, and stored digitally. All images were retrospectively reviewed by two experienced observers. During the analysis coronary vessel dominance, the culprit vessel and culprit lesion and severity of CAD were recorded. A coronary artery system was classified as right dominant if the PDA and posterolateral branch originated from the RCA, left dominant if the PDA and the posterolateral branch originated from the LCx artery, and balanced if the PDA originated from the RCA in combination with posterolateral branches originating from the LCx artery. The culprit vessel was determined on the coronary artery territory subtended by the regions of acute electrocardiographic changes. If the culprit vessel had more than two lesions, the most severe proximal stenosis or a stenosis identified with thrombus was considered the culprit lesion. The extent of CAD was expressed as the presence of one-, two- or three-vessel disease (stenosis causing ≥50% luminal narrowing). Complete revascularization was defined as treating all present significant coronary artery stenosis (≥70% luminal narrowing) during primary PCI or during secondary revascularization before discharge.
After discharge, patients were followed according to the institutional STEMI protocol. By reviewing medical records, retrieval of survival status through municipal civil registries and telephone interviews, data on the occurrence of adverse events after discharge were collected. The adverse events included non-fatal reinfarction and all-cause mortality during follow-up. Non-fatal reinfarction was defined based on criteria of typical chest pain, elevated cardiac enzyme levels, and typical changes on the electrocardiogram. The primary cause of death was recorded and all deaths were classified as cardiac unless unequivocally proven non-cardiac.
The primary endpoint was all-cause mortality. The secondary endpoint was the composite of reinfarction and cardiac death. Short- and long-term outcome after STEMI were investigated using these endpoints. Short-term outcome was defined as within the first 30 days post-STEMI.
Follow-up was updated regularly until 2012. Patients with <2 years of follow-up after STEMI, but who were alive according to the municipal civil registries, were considered lost to follow-up. Data of these patients were included up to the last date of follow-up.
Continuous variables are presented as mean ± standard deviation or as median and interquartile range. Categorical variables are presented as number and percentages. Differences in baseline characteristics between the three coronary vessel dominance groups were evaluated with one-way analysis of variance and Chi-squared tests, where appropriate. To estimate the cumulative incidences of the primary and secondary endpoints during long-term follow-up, Kaplan–Meier analyses stratified for coronary vessel dominance were performed. In addition, to investigate the difference in short-term outcome between the different coronary vessel dominance groups, multivariate binary logistic regression analysis was performed with the endpoints 30-day mortality and the occurrence of reinfarction within 30-days post-STEMI. The number of covariables included in the analysis was adjusted to the number of events and complete availability, resulting in inclusion of the clinical risk factors: age, gender, diabetes, hypertension, and smoking. The results of the binary logistic regression analysis were reported as adjusted odds ratios (ORs) with 95% confidence intervals (CIs). Subsequently, the influence of coronary vessel dominance on long-term outcome was evaluated using the Cox regression analysis in a subgroup of patients surviving the first 30 days after STEMI. In the multivariate Cox regression model, the covariables were selected based upon univariate significance of P-value ≤0.20 and/or significant difference in baseline distribution among the vessel dominance groups, resulting in inclusion of age, gender, diabetes, hypertension, smoking, Killip class during STEMI, three-vessel disease, peak cardiac troponin T, glomerular filtration rate, left-ventricular ejection fraction, and finally reinfarction within the first 30 days post-STEMI was corrected for to adjust for its effect on long-term outcome in the survivors of the 30 days post-STEMI. The results of the Cox regression analysis were reported as adjusted hazard ratios (HRs) with 95% CIs. In addition, Bootstrap validation for model optimism was performed to test whether the parameter estimates were stable in the Cox regression analysis. Statistical analysis was performed using SPSS software (version 20.0, SPSS, Inc., Chicago, IL, USA). A P-value of <0.05, by a two-sided test, was considered statistically significant.
Methods
Patients
The population consisted of consecutive patients presenting with first STEMI at the Leiden University Medical Center between 2004 and 2008. Patients with previous myocardial infarction, previous percutaneous coronary intervention (PCI), and/or previous coronary artery bypass grafting were excluded. The diagnosis of STEMI was defined based on criteria of typical chest pain, elevated cardiac enzyme levels, and typical changes on the electrocardiogram. All patients were treated according to the institutional MISSION! protocol, based upon the European Society of Cardiology and American College of Cardiology/American Heart Association guidelines. The protocol includes primary PCI, optimal medical therapy initiated early during hospitalization, and two-dimensional echocardiography performed within 48 h of admission to assess residual left ventricular function.
Demographic, clinical, angiographic, and echocardiographic data were prospectively collected in the departmental Cardiology Information System (EPD-Vision®, Leiden University Medical Center, Leiden, The Netherlands) and retrospectively analysed. Patients with uninterpretable coronary angiographic images for coronary vessel dominance were excluded from analysis.
Primary Percutaneous Coronary Intervention and Angiographic Data Analysis
Images of the coronary angiography and PCI were obtained using standardized angiographic projections according to the guidelines of the American College of Cardiology/American Heart Association, and stored digitally. All images were retrospectively reviewed by two experienced observers. During the analysis coronary vessel dominance, the culprit vessel and culprit lesion and severity of CAD were recorded. A coronary artery system was classified as right dominant if the PDA and posterolateral branch originated from the RCA, left dominant if the PDA and the posterolateral branch originated from the LCx artery, and balanced if the PDA originated from the RCA in combination with posterolateral branches originating from the LCx artery. The culprit vessel was determined on the coronary artery territory subtended by the regions of acute electrocardiographic changes. If the culprit vessel had more than two lesions, the most severe proximal stenosis or a stenosis identified with thrombus was considered the culprit lesion. The extent of CAD was expressed as the presence of one-, two- or three-vessel disease (stenosis causing ≥50% luminal narrowing). Complete revascularization was defined as treating all present significant coronary artery stenosis (≥70% luminal narrowing) during primary PCI or during secondary revascularization before discharge.
Follow-up and Endpoint Definitions
After discharge, patients were followed according to the institutional STEMI protocol. By reviewing medical records, retrieval of survival status through municipal civil registries and telephone interviews, data on the occurrence of adverse events after discharge were collected. The adverse events included non-fatal reinfarction and all-cause mortality during follow-up. Non-fatal reinfarction was defined based on criteria of typical chest pain, elevated cardiac enzyme levels, and typical changes on the electrocardiogram. The primary cause of death was recorded and all deaths were classified as cardiac unless unequivocally proven non-cardiac.
The primary endpoint was all-cause mortality. The secondary endpoint was the composite of reinfarction and cardiac death. Short- and long-term outcome after STEMI were investigated using these endpoints. Short-term outcome was defined as within the first 30 days post-STEMI.
Follow-up was updated regularly until 2012. Patients with <2 years of follow-up after STEMI, but who were alive according to the municipal civil registries, were considered lost to follow-up. Data of these patients were included up to the last date of follow-up.
Statistical Analysis
Continuous variables are presented as mean ± standard deviation or as median and interquartile range. Categorical variables are presented as number and percentages. Differences in baseline characteristics between the three coronary vessel dominance groups were evaluated with one-way analysis of variance and Chi-squared tests, where appropriate. To estimate the cumulative incidences of the primary and secondary endpoints during long-term follow-up, Kaplan–Meier analyses stratified for coronary vessel dominance were performed. In addition, to investigate the difference in short-term outcome between the different coronary vessel dominance groups, multivariate binary logistic regression analysis was performed with the endpoints 30-day mortality and the occurrence of reinfarction within 30-days post-STEMI. The number of covariables included in the analysis was adjusted to the number of events and complete availability, resulting in inclusion of the clinical risk factors: age, gender, diabetes, hypertension, and smoking. The results of the binary logistic regression analysis were reported as adjusted odds ratios (ORs) with 95% confidence intervals (CIs). Subsequently, the influence of coronary vessel dominance on long-term outcome was evaluated using the Cox regression analysis in a subgroup of patients surviving the first 30 days after STEMI. In the multivariate Cox regression model, the covariables were selected based upon univariate significance of P-value ≤0.20 and/or significant difference in baseline distribution among the vessel dominance groups, resulting in inclusion of age, gender, diabetes, hypertension, smoking, Killip class during STEMI, three-vessel disease, peak cardiac troponin T, glomerular filtration rate, left-ventricular ejection fraction, and finally reinfarction within the first 30 days post-STEMI was corrected for to adjust for its effect on long-term outcome in the survivors of the 30 days post-STEMI. The results of the Cox regression analysis were reported as adjusted hazard ratios (HRs) with 95% CIs. In addition, Bootstrap validation for model optimism was performed to test whether the parameter estimates were stable in the Cox regression analysis. Statistical analysis was performed using SPSS software (version 20.0, SPSS, Inc., Chicago, IL, USA). A P-value of <0.05, by a two-sided test, was considered statistically significant.