Stratification of cardiovascular risk by cardiac computerized tomography: shall we keep on ignoring?

LETTER TO THE EDITOR

Stratification of cardiovascular risk by cardiac computerized tomography - shall we keep on ignoring?

Marcelo Souto Nacif^I; Adriana Dias Barranhas^II

^IUniversidade Federal Fluminense (UFF), Niterói

^IIUniversidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ - Brazil

^{Mailing Address}

Keywords: Risk Assessment; Calcium; Coronary Angiography; Coronary Disease; Tomography, Computed.

In Volume 98, Issue 6, June 2012, we read with great interest the article written by Azevedo et al¹, in which the role of calcium scoring and coronary CT angiography in cardiovascular risk stratification was extensively discussed. The issue deserves thorough scientific discussion and the transition to everyday clinical practice should be rethought.

Although the intention has been to conduct a review based on scientific evidence in the literature, which often makes reference to populations not comparable to ours, it was observed that many of the studies used as scientific evidence represent a large portion of the Brazilian population. Examples of such are the works of Monteiro et al², Rosario et al³ and Azevedo et al⁴, in addition to the important CORE 64⁵, in which Brazil was the country that included the most patients.

We believe that the scientific base was very well prepared, but it lacked in discussing the transition to clinical practice. This is extremely important in line with the authors' experience, mainly due to the lack of Brazilian guideline updates, which are dated from 2006⁶. In the last six years, clinical practice highlights the significant increase in the use of cardiac computed tomography (CCT), given that some services already use this method as a first option in cardiovascular risk stratification by noninvasive imaging.

Reinforcing that CCT is more than ready for use in daily clinical practice, the National Supplementary Health Agency (ANS) included computed angiotomography in the list of CT procedures, but what mostly caught our attention was the exclusion of the coronary calcium score, a technique that has higher scientific backing. Thus, two questions remain unanswered - what scientific evidence is still needed? Why are calcium scoring and coronary CT angiography not being widely used in clinical practice?

We believe this revision work was well done, but we find the discussion of the scientific evidence and its implementation in clinical practice to be very relevant. We know that cardiovascular risk stratification is of fundamental importance and, as doctors, we should offer the best medicine available to our population. Therefore, we suggest that we should not continue ignoring the CCT as a method of cardiovascular risk stratification.

References

Manuscript received July 06, 2012; revised manuscript February 01, 2013; accepted February 01, 2013.

Reply

We would like to thank Doctors Nacif and Barranhas for their interest in our article¹ and for the opportunity to further discuss the application of calcium scoring in current clinical practice. We agree there is already a large volume of robust scientific evidence demonstrating the value of coronary calcium scoring in the stratification of cardiovascular risk of asymptomatic^2-5 individuals. So why is it still not systematically used in everyday clinical practice? We believe that several factors are involved in the response to this question. The first factor relates to the concept of translational medicine, i.e., the long time interval existing between a new medical intervention (a new diagnostic test, a new drug or therapeutic procedure, for example) that has been discovered/proposed and its widespread implementation in clinical practice. This process is essential not only to test the safety and efficacy of the new procedure before it is used on patients, but also to be able to assess the cost-effectiveness of the proposed intervention. For some procedures, this process is simpler, and the "translational gap" is shorter. In the case of calcium scoring, due to the fact that it involves the use of ionizing radiation, and mainly because the method is being proposed as a screening test in asymptomatic individuals, the process becomes longer, arid and more time- consuming. Nevertheless, we believe that, at the moment, we can say with certainty that calcium scoring "passed" with flying colors throughout this entire process and, in the words of Doctors Nacif and Barranhas, it is more than ready to be integrated in daily clinical practice.

The second factor relates to the potential of the proposed procedure to change the clinical management of patients. At this point, calcium scoring still has long way to go. Even though, as reported in our revision paper, some important recent studies have shown that calcium scoring has the potential to become an essential tool in clinical decision-making^6,7, this process is still incipient. Currently, calcium scoring has not yet been inserted in decision-making algorithms. We believe it is only a matter of time until calcium scoring is a part, for example, of the algorithms that define treatment with statins. However, before that happens, further studies are needed to better define the role of calcium scoring in each of the different clinical situations and how its outcome will help define clinical management. From our standpoint, this is one of the most relevant factors that still limits the wider use of calcium scoring in current clinical practice.

The third factor relates to the difficulty in obtaining permission for the examination by health plans. According to the most recent determination of the National (Supplementary) Health Agency, coronary calcium scoring is not included in the list of medical procedures compulsorily covered by health plans. For this reason, most of these plans do not authorize this procedure, even when prompted appropriately - in order to stratify the cardiovascular risk of the patient. Considering the volume and solidness of evidence in favor of calcium scoring accumulated over the last decade, we are convinced that it is time for the National Health Agency to review its position and include it in the list of compulsory medical procedures. In the face of current evidence, we have no doubt that, when properly indicated, calcium scoring will bring great benefit to patients and be confirmed as a cost-effective tool in cardiovascular risk stratification.

Sincerely,

Clerio F. Azevedo

Carlos E. Rochitte

João A. C. Lima

References

Correspondência:

Marcelo Souto Nacif

Rua Barão de Cocais, 324, Bosque Imperial

CEP 12242-042, São José dos Campos, SP - Brasil

E-mail: [e-mail], [e-mail]

Artigo recebido em 06/07/12; revisado em 01/02/13; aceito em 01/02/13.

Carta-resposta

Gostaríamos de agradecer aos Doutores Nacif e Barranhas pelo interesse em nosso artigo¹ e pela oportunidade de aprofundar a discussão sobre a aplicação do escore de cálcio na prática clínica atual. Concordamos que já existe grande volume de evidências científicas robustas que demonstra o valor do escore de cálcio coronariano na estratificação do risco cardiovascular de indivíduos assintomáticos^2-5. Então, por que ele ainda não é utilizado de forma sistemática na prática clínica do dia a dia? Acreditamos que alguns fatores estão envolvidos na resposta a essa questão. O primeiro fator diz respeito ao conceito de medicina translacional, ou seja, o longo processo existente entre uma nova intervenção médica (um novo exame diagnóstico, um novo medicamento ou procedimento terapêutico, por exemplo) ser descoberta/proposta e sua ampla implementação na prática clínica. Esse processo é fundamental não apenas para testar a eficácia e a segurança do novo procedimento antes que ele seja utilizado nos pacientes, mas também para que se possa avaliar a relação de custo-efetividade da intervenção proposta. Para alguns procedimentos, esse processo é mais simples, e o "intervalo translacional", mais curto. No caso do escore de cálcio, devido ao fato de envolver o uso de radiação ionizante e, principalmente, porque o método está sendo proposto como um exame de screening em indivíduos assintomáticos, o processo torna-se mais longo, árido e demorado. Não obstante, acreditamos que, no momento, já podemos dizer que o escore de cálcio "passou" com louvor por todo esse processo e, nas palavras dos Doutores Nacif e Barranhas, está mais do que pronto para sua inserção na prática clínica cotidiana.

O segundo fator diz respeito ao potencial que o procedimento proposto tem de mudar a conduta clínica dos pacientes. Nesse ponto, o escore de cálcio ainda tem muito a avançar. Ainda que, como relatado em nosso artigo de revisão, alguns importantes estudos recentes tenham demonstrado que o escore de cálcio tem o potencial de se tornar uma ferramenta fundamental na tomada de decisão clínica^6,7, esse processo ainda é incipiente. Atualmente, o escore de cálcio ainda não está inserido nos algoritmos de tomada de decisão. Acreditamos que seja uma questão de tempo até que o escore de cálcio faça parte, por exemplo, dos algoritmos que definem o tratamento com estatinas. Entretanto, antes que isso aconteça, novos estudos serão necessários para definir melhor o papel do escore de cálcio em cada uma das diferentes situações clínicas e como seu resultado ajudará a definir a conduta clínica. Do nosso ponto de vista, esse é um dos fatores mais relevantes e que ainda limitam o uso mais amplo do escore de cálcio na prática clínica atual.

O terceiro fator diz respeito à dificuldade com a autorização do exame por parte dos planos de saúde. Segundo a determinação mais recente da Agência Nacional de Saúde Suplementar (ANS), o escore de cálcio coronariano não consta no rol de procedimentos médicos com cobertura obrigatória pelos planos de saúde. Por esse motivo, a maior parte deles não autoriza sua realização, mesmo quando solicitado de forma apropriada - com o objetivo de estratificar o risco cardiovascular do paciente. Considerando o volume e a robustez das evidências em favor do escore de cálcio acumuladas ao longo da última década, temos a convicção de que já está na hora da ANS rever sua posição e incluí-lo no rol dos procedimentos médicos obrigatórios. Frente às evidências atuais, não temos dúvida de que, quando bem indicado, o escore de cálcio trará grande benefício aos pacientes e se confirmará como uma ferramenta custo-efetiva na estratificação do risco cardiovascular.

Atenciosamente,

Clerio F. Azevedo

Carlos E. Rochitte

João A. C. Lima

Referências

• 1. Azevedo CF, Rochitte CE, Lima JAC. Escore de cálcio e angiotomografia coronariana na estratificação do risco cardiovascular. Arq Bras Cardiol. 2012;98(6):559-68.
• 2. Monteiro VS, Lacerda HR, Uellendahl M, Chang TM, Albuquerque VM, Zirpoli JC, et al. [Calcium score in the evaluation of atherosclerosis in patients with HIV/Aids]. Arq Bras Cardiol. 2011;97(5):427-33.
• 3. Rosario MA, Lima JJ, Parga JR, Avila LF, Gowdak LH, Lemos PA, et al. [Coronary calcium score as predictor of stenosis and events in pretransplant renal chronic failure]. Arq Bras Cardiol. 2010;94(2):236-43, 252-60, 239-47.
• 4. de Azevedo CF, Hadlich MS, Bezerra SG, Petriz JL, Alves RR, de Souza O, et al. Prognostic value of CT angiography in patients with inconclusive functional stress tests. JACC Cardiovascular Imaging. 2011;4(7):740-51.
• 5. Miller JM, Rochitte CE, Dewey M, Arbab-Zadeh A, Niinuma H, Gottlieb I, et al. Diagnostic performance of coronary angiography by 64-row CT. N Engl J Med. 2008;359(22):2324-36.
• 6. Rochitte CE, Pinto IM, Fernandes JL, Filho CF, Jatene A, Carvalho AC, et al; Grupo de Estudos de Ressonância e Tomografia Cardiovascular (GERT) do Departamento de Cardiologia Clínica da Sociedade Brasileira de Cardiologia, [I cardiovascular magnetic resonance and computed tomography guidelines of the Brazilian Society of Cardiologia - Executive summary]. Arq Bras Cardiol. 2006;87(3):e48-59.
• 1. Azevedo CF, Rochitte CE, Lima JA. [Coronary artery calcium score and coronary computed tomographic angiography for cardiovascular risk stratification]. Arq Bras Cardiol. 2012;98(6):559-68.
• 2. Greenland P, Alpert JS, Beller GA, Benjamin EJ, Budoff MJ, Fayad ZA, et al; American College of Cardiology Foundation; American Heart Association. 2010 ACCF/AHA guideline for assessment of cardiovascular risk in asymptomatic adults: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol.2010;56(25):e50-103.
• 3. Greenland P, Bonow RO, Brundage BH, Budoff MJ, Eisenberg MJ, Grundy SM,et al; American College of Cardiology Foundation Clinical Expert Consensus Task Force (ACCF/AHA Writing Committee to Update the 2000 Expert Consensus Document on Electron Beam Computed Tomography); Society of Atherosclerosis Imaging and Prevention; Society of Cardiovascular Computed Tomography. ACCF/AHA 2007 clinical expert consensus document on coronary artery calcium scoring by computed tomography in global cardiovascular risk assessment and in evaluation of patients with chest pain: a report of the American College of Cardiology Foundation Clinical Expert Consensus Task Force (ACCF/AHA Writing Committee to Update the 2000 Expert Consensus Document on Electron Beam Computed Tomography) developed in collaboration with the Society of Atherosclerosis Imaging and Prevention and the Society of Cardiovascular Computed Tomography. J Am Coll Cardiol.2007;49(3):378-402.
• 4. Rochitte CE. [The role of the Arquivos Brasileiros de Cardiologia in the new era of non-invasive cardiovascular imaging]. Arq Bras Cardiol. 2012;98(1):3-5.
• 5. Rochitte CE, Pinto IM, Fernandes JL, Filho CF, Jatene A, Carvalho AC, et al.Grupo de Estudo em Ressonância e Tomografia Cardiovascular (GERT) do Departamento de Cardiologia Clínica da Sociedade Brasileira de Cardiologia. [Cardiovascular magnetic resonance and computed tomography imaging guidelines of the Brazilian Society of Cardiology]. Arq Bras Cardiol. 2006;87(3):e60-100.
• 6. Kalia NK, Miller LG, Nasir K, Blumenthal RS, Agrawal N, Budoff MJ. Visualizing coronary calcium is associated with improvements in adherence to statin therapy. Atherosclerosis.2006;185(2):394-9.
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Publication Dates

• Publication in this collection
  28 May 2013
• Date of issue
  May 2013