Red Blood Cell Distribution Width


Academician Project, National Academy of Science and Technology Professor Emeritus, College of Medicine, UP Manila

Dr. Ramon F. Abarquez, Jr. has been one of the most prolific consultant writers of H&L and its sister publication, Vital Signs. Highly esteemed in the medical community, he is the founding president of Philippine Society of Hypertension and apast president of the Philippine College of Physicians

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Red blood cell distribution width (RDW) is a measure of red blood cell volume variations (anisocytosis), reported in standard complete blood count. Red cells can penetrate any stenotic coronary vessels as a predictor of poor clinical outcomes in the settings of various diseases, including coronary artery disease (CAD).

The negative prognostic effects of elevated RDW levels may be attributed to the adverse effects of independent risk factors such as inflammation, oxidative stress, and vitamin D3 and iron deficiency on bone marrow function (erythropoiesis).

Elevated RDW values may reflect the intensity of these phenomena and their unfavorable impacts on bone marrow erythropoiesis. Furthermore, decreased red blood cell deformability among patients with higher RDW values impairs blood flow through the microcirculation, resulting in the diminution of oxygen supply at the tissue level, particularly among patients suffering from myocardial infarction treated with urgent revascularization. [Bujak, Dis Markers. 2015;2015:824624]

Acute coronary syndrome

Overall, increased RDW value is associated with increased risk of acute coronary syndrome (ACS) [including acute myocardial infarction (AMI)], ischemic cerebrovascular disease (including stroke), peripheral artery disease (PAD), as well as with atrial fibrillation (AF), heart failure (HF) and hypertension.

Higher anisocytosis also significantly and independently predicts adverse outcomes in patients with these conditions, although the role of anisocytosis in the pathogenesis of cardiovascular diseases remains uncertain. [Danese, J Thorac Dis. 2015 Oct;7(10):E402-11]

A total of 107 publications regarding occlusive vascular diseases, 80.3 percent on prognostic and 19.6 percent are on diagnostics. In 95.3 percent of prognostic publications, there was a positive correlation between high NLR values at admission and poor prognosis. In 95.3% of diagnostic publications high NLR values at admission were identified to be significant diagnostically. [Kucuk, World J Emerg Med. 2016;7(3):165-72]

AF catheter ablation

Multivariate analysis demonstrated that RDW (hazard ratio 1.20, 1.01-1.40, P=0.034) was an independent predictor of AF recurrence in the HF group. The cut-off values of RDW for the recurrence of AF and major adverse events in the HF group were 13.9% and 14.8%, respectively. RDW is a potential noninvasive marker in AF patients complicated with HF. [Yanagisawa, Circ J 2016; 80: 627-638].

CBC and no-reflow

The no-reflow (NR) phenomenon represents an acute reduction in coronary blood flow without coronary vessel obstruction, coronary vessel dissection, spasm, or thrombosis, particularly among patients with acute STE myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI).

Automated cell counters are routinely available in many clinical laboratories and can be used to determine red blood cell distrubiton width (RDW), platetecrit, platelet count, and and some ratios like the neutrophillymphocyte ratio and RDW-platelet ratio.

These hematological markers are independent predictors of impaired angiographic reperfusion and long-term mortality among patients with STEMI undergoing pPCI. [Celik, Angiology. 2016 Jul 14)

Higher monocyte count (0.76 ± 0.48 × 109/L vs. 0.55 ± 0.29 × 109/L, p = 0.004) on admission and low hemoglobin concentration were independent clinical predictors of no-reflow following pPCI in patients with STEMI. [Wang, Kardiol Pol. 2016;74(10):1160-1166]

Higher admission neutrophil counts (9.02 ± 3.97 × 109/L vs 7.57 ± 2.82 × 109/L, P = 0.007), high-sensitivity C-reactive protein (hsCRP), white blood counts, monocyte counts were significantly predictors. [Wang, Acta Cardiol. 2016 Apr;71(2):241-6]

Reperfusion pre-test

CAD is more common among older, women, and hypertensive patients. Elevated RDW strongly correlated with TIMI flow less than 3 (P<0.001) and is an independent predictor of abnormal reperfusion in multivariate regression analysis (odds ratio: 2.20, 1.012-4.569; P=0.05). [Karabulut, Coron Artery Dis. 2012 Jan;23(1):68-72.]

But, despite a higher rate of MACE in reperfused STEMI patients, antecedent hypertension group versus no HTN group showed no difference in reperfusion efficacy, infarct size and reperfusion injury, based on CMR. [Reinstadler, J Cardiovasc Magn Reson. 2016 Nov 11;18(1):80] CBC components is MACE morbidity and mortality pre-test.