Prognostic factors in patients with acute coronary syndrome without ST-segment elevation

LETTER TO THE EDITOR

Prognostic factors in patients with acute coronary syndrome without ST-segment elevation

Sinan İşcen

Diyarbakır Military Hospital, Yenısehır, Dıyarbakır

^{Mailing Address}

Keywords: Acute Coronary Syndrome; Inflammation; Myocardial Infarction, Prognosis, Lymphopenia.

Dear Editor,

We read the article, "Prognostic factors in patients with acute coronary syndrome without ST-segment elevation" written by Santos JC¹. The authors concluded that the assessment of renal function and lymphocyte count provide potentially useful information for the prognostic stratification of patients with non-ST elevation ACS.

We know that patients with end-stage renal disease have a higher risk for and a worse outcome after myocardial infarction. However, lesser degrees of renal dysfunction also predict an adverse prognosis in patients with acute MI.

Several studies have shown the magnitude of this effect².

We also know that patients with a higher white blood cell (WBC) count - which is a marker of inflammation, have an increased risk for adverse events, in-hospital mortality, and short- and long-term mortality after a non-ST elevation ACS, as well as for acute ST-elevation MI³. The value of the baseline WBC in patients with non-ST-elevation MI or unstable angina was evaluated in the TACTICS-TIMI 18 trial⁴, which concluded that higher WBC was associated with significantly lower TIMI flow grades, myocardial perfusion grades and more extensive coronary disease. This was found in relation to WBC but not to lymphocytes, because many factors in the ICU environment may lead to lymphocytopenia (trauma, hemorrhage, viral infections, etc.). Therefore, in order to establish a relationship between lymphocyte count and prognosis, further evaluation and objective evidence are needed.

References

Manuscript received 04/15/13; revised manuscript received 04/17/13; accepted 06/20/13.

Reply

As regards Dr. İşcen's comments, we have some points to consider.

All patients diagnosed with unstable angina (UA) or non-ST segment elevation (STE) acute myocardial infarction (AMI) admitted to our hospital from Janurary to December 2010 were included in our study. In an attempt to eliminate possible confounders, patients presenting with malignant neoplasias, infectious diseases, autoimmune diseases, and those who had recently suffered a trauma or undergone surgery - conditions which could lead to leukocytosis, neutrophilia or lymphopenia, were excluded. The inclusion and exclusion criteria were described in the respective article¹.

We verified that complete white blood cell and neutrophil counts in our sample were not able to discriminate patients at a higher risk for adverse events (7781 ± 3252 /mm³ vs. 8140 ± 2835 /mm³, p = 0.5; and 5653 ± 3058 /mm³ vs. 5220 ± 2496 /mm³, p = 0.4, respectively). However, the logistic regression analysis showed an independent and significant relationship between lymphocyte count and combined events (OR: 1.02; 95%CI: 1.01-1.04; p = 0.03). Some studies have suggested that the count of leukocytes and their subpopulations may predict fatal and non-fatal outcomes in patients with non-STE acute coronary syndrome^2,3. Cannon et al⁴ and Núñez et al⁵ demonstrated that the relationship between leukocytosis, neutrophilia and a worse prognosis is valid for patients with AMI, but not for those with UA. Lloyd-Jones et al⁶ and Zouridakis et al⁷ found that only lymphopenia, among the subpopulations of white blood cells, was associated with future cardiac events in these patients. Since, in our article¹, two thirds of our sample was comprised of patients with UA, we suggested that the lymphocyte count in this population probably provides a better identification of patients with a worse prognosis.

Sincerely,

Jessica C M D'Almeida Santos

Mário de Seixas Rocha

Marcos da Silva Araújo

References

Correspondência:

Sinan İşcen

Diyarbakır Military Hospital, Yenısehır

CEP 34100, Dıyarbakır

E-mail: [e-mail]

Artigo recebido em 15/04/13; revisado em 17/04/13; aceito em 20/06/13.

Carta-resposta

Com relação ao que foi comentado, temos algumas ponderações:

No nosso estudo foram incluídos todos os pacientes com o diagnóstico de Angina Instável (AI) ou Infarto Agudo do Miocárdio (IAM) sem Supradesnível de ST (SST), admitidos no hospital no período de janeiro a dezembro de 2010. Na tentativa de eliminar possíveis fatores de confusão, excluímos pacientes que apresentavam: neoplasias malignas, doenças infecciosas, doenças autoimunes, e aqueles que sofreram trauma ou cirurgia recente; patologias essas que podem levar a leucocitose, neutrofilia ou linfopenia. Os critérios de inclusão e exclusão estão presentes no texto do artigo¹.

Constatamos que, na nossa amostra, a contagem total de células brancas e a contagem de neutrófilos não foram capazes de discriminar aqueles pacientes com maior risco de eventos adversos (7781 ± 3252 /mm³ vs. 8140 ± 2835 /mm³, p = 0,5; e 5653 ± 3058 /mm³ vs. 5220 ± 2496 /mm³, p = 0,4; respectivamente). Entretanto, a análise de regressão logística demonstrou uma relação independente e significativa entre a contagem de linfócitos e os eventos combinados (OR:1,02; IC95%:1,01-1,04; p = 0,03). Alguns estudos sugerem que a contagem de leucócitos e suas subpopulações pode predizer desfechos fatais e não-fatais em pacientes com síndrome coronariana aguda sem SST^2,3. Cannon e cols.⁴ e Núñez e cols.⁵ demonstraram que a relação entre leucocitose, neutrofilia e pior prognóstico é verdadeira em pacientes com IAM, mas não se mantem naqueles com AI. Lloyd-Jones e cols.⁶ e Zouridakis e cols.⁷ constataram que nestes pacientes somente a linfopenia, dentre as subpopulações de células brancas, esteve associada com eventos cardíacos futuros. Dado que dois terços de nossa amostra foi representada por pacientes com AI, sugerimos no artigo¹ que nessa população a contagem de linfócitos provavelmente identifica melhor aqueles com pior prognóstico.

Atenciosamente,

Jessica C M D'Almeida Santos

Mário de Seixas Rocha

Marcos da Silva Araújo

Referências

• 1. Santos JC, Rocha Mde S, Araújo Mda S. Prognostic factors in patients with acute coronary syndrome without ST segment elevation. Arq Bras Cardiol. 2013;100(5):412-21.
• 2. Al Suwaidi J, Reddan DN, Williams K, Pieper KS, Harrington RA, Califf RM, et al; GUSTO-IIb, GUSTO-III, PURSUIT. Global Use of Strategies to Open Occluded Coronary Arteries. Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy; PARAGON-A Investigators. Platelet IIb/IIIa Antagonism for the Reduction of Acute coronary syndrome events in a Global Organization Network. Prognostic implications of abnormalities in renal function in patients with acute coronary syndromes. Circulation. 2002;106(8):974-80.
• 3. Madjid M, Awan I, Willerson JT, Casscells SW. Leukocyte count and coronary heart disease: implications for risk assessment. J Am Coll Cardiol. 2004;44(10):1945-56.
• 4. Sabatine MS, Morrow DA, Cannon CP, Murphy SA, Demopoulos LA, DiBattiste PM, et al. Relationship between baseline white blood cell count and degree of coronary artery disease and mortality in patients with acute coronary syndromes: a TACTICS-TIMI 18 (Treat Angina with Aggrastat and determine Cost of Therapy with an Invasive or Conservative Strategy- Thrombolysis in Myocardial Infarction 18 trial)substudy. J Am Coll Cardiol. 2002;40(10):1761-8.
• 1. Santos JC, Rocha Mde S, Araújo Mda S. Prognostic factors in patients with acute coronary syndrome without ST segment elevation. Arq Bras Cardiol. 2013;100(5):412-21.
• 2. Barron HV, Cannon CP, Murphy SA, Braunwald E, Gibson CM. Association between white blood cell count, epicardial blood flow, myocardial perfusion, and clinical outcomes in the setting of acute myocardial infarction: a thrombolysis in myocardial infarction 10 substudy. Circulation. 2000;102(19):2329-34.
• 3. Furman MI, Gore JM, Anderson FA, Budaj A, Goodman SG, Avezum A, et al. Elevated leukocyte count and adverse hospital events in patients with acute coronary syndromes: findings from the Global Registry of Acute Coronary Events (GRACE). Am Heart J. 2004;147(1):42-8.
• 4. Cannon CP, McCabe CH, Wilcox RG, Bentley JH, Braunwald E. Association of white blood cell count with increased mortality in acute myocardial infarction and unstable angina pectoris. OPUS-TIMI 16 Investigators. Am J Cardiol. 2001; 87(5):636-9.
• 5. Núñez J, Sanchis J, Bodí V, Nunez E, Mainar L, Heatta AM, et al. Relationship between low lymphocyte count and major cardiac events in patients with acute chest pain, a non-diagnostic electrocardiogram and normal troponin levels. Atherosclerosis. 2009;206(1):251-7.
• 6. Lloyd-Jones DM, Camargo CA Jr, Giugliano RP, O'Donnell CJ. Effect of leukocytosis at initial examination on prognosis in patients with primary unstable angina. Am Heart J. 2000;139(5):867-73.
• 7. Zouridakis EG, Garcia-Moll X, Kaski JC. Usefulness of the blood lymphocyte count in predicting recurrent instability and death in patients with unstable angina pectoris. Am J Cardiol. 2000;86(4):449-51.

Publication Dates

• Publication in this collection
  05 Nov 2013
• Date of issue
  Oct 2013