Coronary Dominance Plays Role in Early Post-STEMI Mortality Risk

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In patients with ST-segment elevation myocardial infarction (STEMI), a left-dominant coronary artery system is linked with higher risk of 30-day mortality and early reinfarction compared with right-dominant anatomy, according to a study published online June 13, 2014, ahead of print in the European Heart Journal. However, coronary vessel dominance does not seem to affect longer-term outcomes. 

Methods
Researchers led by Arthur J. H. A. Scholte, MD, of LeidenUniversity Medical Center (Leiden, the Netherlands), stratified 1,131 patientswith first STEMI into groups based on their coronary anatomy; most had a right-dominantsystem (n = 971), while almost one-tenth had a left-dominant system (n = 102)and 58 patients had a balanced system.
Overall, baseline characteristics were similar among thegroups. However, patients with a balanced system tended to be younger, andpatients with a left-dominant system more frequently had hypertension. The RCAwas most often the culprit vessel in patients with a right-dominant system,whereas the LAD was the culprit vessel in most patients with left-dominant orbalanced systems. The majority of patients presented with single-vesseldisease, and primary PCI resulted in complete revascularization in 70% ofpatients.

 

HigherRisk for Left-Dominant Systems

At 5 years, cumulative incidences of all-cause mortality(primary endpoint; log-rank P = .013)and combined reinfarction and cardiac death (secondary endpoint; log-rank P = .007) were higher in patients with aleft-dominant system compared with either a right-dominant or balanced system.

On multivariate analysis, left coronary vessel dominance andage were independent predictors of both primary and secondary endpoints within30 days (table 1).

Table1. Independent Predictors of Adverse Events at 30 Days

   
OR
 
95% CI
 
P Value
Older Age 
All-Cause Death 
Reinfarction/Cardiac Death 


1.10 
1.06 

1.06-1.14 
1.03-1.09 

< .001 
.001 
Left Dominant Coronary Artery System 
All-Cause Death 
Reinfarction/Cardiac Death 


2.51 
2.25

1.11-5.67 
1.09-4.61 

.027 
.028 



However, in patients surviving past 30 days (n = 1,086),coronary vessel dominance no longer predicted either the primary or secondaryoutcome. Instead, older age, male gender, and higher peak cardiac troponin Tlevel were independently associated with all-cause death after 30 days.

Of the 119 patients who died within the median follow-upperiod of 48 months, 45 died within the first 30 days after STEMI including 25within the first 24 hours. Most early mortality was classified as cardiac death,primarily due to cardiogenic shock. Furthermore, 24 patients (2%) hadreinfarction within 30 days after STEMI.

InfarctLocation Matters

The more than doubled risk for 30-day mortality in patientswith a left vs right dominant system “can be explained by the impact coronaryanatomy has on the extent of the infarcted area and recovery of leftventricular function post-STEMI,” the authors write.

“At 30 days post-STEMI, a natural selection of patients hastaken place, leaving those patients with less severe myocardial infarctions,”they continue. “This mechanism of selection might be influenced by coronarydominance, since the presence of left coronary dominance is hypothesized tolead to a bigger area of jeopardized myocardium in case of left coronaryocclusion.”

However, the lack of association between coronary anatomyand long-term events could be attributed to the fact that “the influence ofcoronary vessel dominance… may be less prominent once surviving the first 30days post-STEMI,” Dr. Scholte and colleagues observe. “This explanation isstrengthened by the fact that the proportion of patients with left dominance issignificantly higher in the deceased compared with the survivors.”

Ajay J. Kirtane, MD, SM, of Columbia University MedicalCenter (New York, NY), agreed, adding that the “challenging thing to sort out with these studies, though, is determining if there is any selection bias inherent in the way we’re identifying [right vs left dominant] MIs.” He told TCTMD in a telephone interview that the number of LAD infarcts was higher in patients who had left vs right dominant circulation.

“When you have right-dominant circulation, the infarcts are often RCA, and so simply having an LAD infarct is worse than having a right coronary infarct,” he continued. “Some of this might be a little bit of confounding, although [the researchers] did adjust for these things in their modeling.”

Another Tool inthe Risk Stratification Box

The results confirm a risk-stratification factor that interventionalists can use to better understand their patients preprocedure, Dr. Kirtane commented.

Similarly, the authors suggest that “the incorporation of coronary anatomy in clinical risk scores and future prognostic analyses in patients with STEMI could improve risk estimation of adverse events during follow-up post-STEMI.” Perhaps more aggressive antiplatelet or anticoagulation therapy could also be considered for this patient group, they say.

 


Source:

Veltman CE, van der Hoeven BL, Hoogslag GE, et al. Influenceof coronary vessel dominance on short- and long-term outcome in patients afterST-segment elevation myocardial infarction. EurHeart J. 2014;Epub ahead of print.

Disclosures:

  • The authors report institutionalresearch support from Biotronik, Boston Scientific, GE Healthcare, LantheusMedical Imaging, Medtronic, and St. Jude Medical.  

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