Correlation Between Red Cell Distribution Width and Coronary Ectasia in the Acute Myocardial Infarction

We read with a great interest the article entitled as “Assessment of red cell distribution width (RDW) in patients with coronary artery ectasia” by Dogdu et al that was published online in August 2011 issue of this journal. ¹ The authors clearly demonstrated the elevated level of RDW in the isolated coronary ectasia (CE). ¹

The RDW is found to be an independent prognostic factor for cardiovascular outcomes and all-cause mortality, even adjustment for multiple potential confounders including anemia.^2–3 Increased level of RDW reflects chronic inflammatory state which is also revealing in the pathophysiologic mechanism of the CE. ⁴ In the acute myocardial infarction (AMI), inflammatory markers usually make peak level that may reflect the accelerated inflammatory process. In such a condition, association between RDW and CE was not investigated before. In addition to the results presented by Dogdu et al, we searched the correlation of RDW and CE in the patients with ST-elevation AMI, and we evaluated whether the correlation between RDW and isolated CE is still valid in the patients with AMI.

A total of 201 patients with an ST-elevation AMI were evaluated retrospectively. Upon admission, RDW was measured by the automated hematology analyzers Sysmex XT-1800i (Roche Diagnostic, Istanbul, Turkey). The patients' angiographic data were evaluated from catheter laboratory records and CE was documented for each patients. Coronary ectasia was defined as a localized or diffuse nonobstructive lesion of the epicardial coronary arteries with a luminal dilation exceeding 1.5-fold the diameter of the normal adjacent arterial segment. ⁵ Then the patients were classified according to the presence of CE, level of RDW, and other clinical and demographic characteristics. The RDW >14.8% was considered as elevated level. All groups were compared by chi-square and Pearson correlation analysis and Mann-Whitney U test according to the presence and distribution of CE.

Coronary ectasia was found in the 24 patients and 15 of the ectatic vessels were also infarct-related artery. Although patients with CE did not differ in terms of age, sex, presence of diabetes mellitus, hypertension, previously diagnosed coronary heart disease, and multivessel disease significantly, elevated level of RDW was more common in the patients with CE (P = .01; Table 1 ). However, isolated ectasia in the infarct-related artery was not correlated with elevated level of RDW (53.3% vs 44.4%; P = .67).

Table 1.

Demographic and Clinical Characteristics and RDW Level According to Presence of Coronary Ectasia

	Coronary Ectasia (+) (n = 24)	Coronary Ectasia (−) (n = 177)	P
Age, years	53.6 ± 8.4	57.2 ± 11.1	.12
Sex (male/female)	95.8% (23)	80.8% (143)	.07
Presence of diabetes mellitus	8.3% (2)	24.9% (44)	.07
Presence of hypertension	62.5% (15)	52.5% (93)	.30
Previous coronary artery disease	16.7% (4)	13.0% (23)	.62
Current smoking	79.2% (19)	62.7% (111)	.11
Multivessel disease	45.8% (11)	58.2% (103)	.25
Elevated RDW (>14.8%)	50.0% (12)	24.3% (43)	.01
Mean RDW level (%)	14.6 ± 1.5	14.0 ± 1.4	.05

Abbreviation: red cell distribution width.

^a P < .05 is significant, indicated as boldface.

Coronary ectasia usually progress on the basis of diffuse atherosclerosis, chronic inflammatory process, and increased oxidative stress. Correlation between elevated level of RDW such mentioned clinical process were also shown with previous studies.^4,6,7 Presence of CE may reflect the further exaggeration of the inflammatory response in the AMI, which could explain the correlation between elevated level of RDW and the CE, even adjustment for the AMI.

In conclusion, elevated RDW level may also reflect CE in the patients with AMI. There was no significant correlation between elevated RDW level and isolated CE in the infarct-related artery.