Menos é Mais ? Medical Therapy of Stable Multivessel Coronary Artery Disease . Less is More ?

A disponibilidade e utilização de mais recursos em Medicina não são sinônimos de melhores resultados no cuidado centrado no paciente. Nos Estados Unidos da América, áreas onde há mais utilização de recursos em comparação a áreas com menos recursos médicos mostram que os resultados com a saúde não são melhores1. Nesse contexto e um cenário de retração econômica, será necessário direcionar com diligência os recursos disponíveis para intervenções de alta complexidade, como cirurgia de revascularização miocárdica (CRVM) e intervenção percutânea coronariana (IPC).


Introduction
The availability and use of additional medical resources are not synonymous with better results in the patientcentered care.In the United States, results in areas in which there are more resources in use have been proven not to be better than those of areas with less medical resources 1 .In this context and in an economic downturn scenario, resources available to highly complex interventions, such as myocardial revascularization surgery (MRS) and percutaneous coronary intervention (PCI), will need to be managed with due care.
Although in recent years the world's leading cardiology societies have reported guidelines and appropriateness criteria for MRS and PCI in coronary artery disease (CAD), many questions still remain about the advantages of one technique over the other, and especially compared to medical treatment (MT) of multivessel CAD.

CAD Treatment -effectiveness
Evidence of MRS and PCI effectiveness to reduce myocardial ischemia in numerous randomized clinical trials (RCTs) conducted over the last few decades has contributed to a wide application of these techniques in the treatment of stable CAD.Although no RCT is proven to increase life expectancy or reduce the incidence of acute myocardial infarction (AMI), when compared to MT or MRS, the assumption that primary PCI benefits are extended to patients with stable CAD and the conception that it poses lower risks when unclogging coronary arteries, made IPC the mostly used revascularization technique worldwide 2 .
The theoretical advantage of PCI over the MT, i.e., all obstruction must be treated, found no support in any RCT dedicated to establish comparison between these therapeutic options 3 .MT has always been underestimated because it was thought to produce bad results, on account of the presence of untreated obstructive lesions, and to be an unsafe and ineffective manner to deal with coronary artery blockages 2 .However, the ECR COURAGE 4 demonstrated that the optimized MT is not only safe but also effective in the treatment of myocardial ischemia.

Multivessel coronary artery disease -how to manage it?
The first RCTs to confront both MRS and MT did not specifically address patients with multivessel CAD.It was intended to prove the advantage of surgical revascularization over MT.In fact, in these RCTs, MRS was confronted with an MT that, when compared to contemporary optimized MT, was little more than a placebo.Additionally, although there were statistically significant differences in subgroups with higher anatomic (left main coronary artery lesion -LMCAL) and functional (extensive ischemia and left ventricular dysfunction) severity, these subgroups were composed of a small number of patients, which produced sample sizes insufficiently large to point out any advantage of a therapeutic option over the other 5 .In addition, there is no contemporary RCT confronting the optimized MT with MRS in LMCAL with good ventricular function, certainly for fear that the mortality and morbidity rates with MT are high, even if this alleged harm caused by MT is questioned 6 .
The evidence unfavorable to TC has as one of its pillars an observational study by Hachamovich et al. 7 However, as this analysis was based on observation and non-randomization, MT patients had many more comorbidities, with it being no surprise, however, that they obtained the worst results 7 .
The debate on the best manner to conduct revascularization in stable CAD gained momentum in recent years due to PCI with drug-eluting stents (DES), but the absence of MT in the RCTs that had used them is a source of frustration.With the investment in the SYNTAX 8 study, for instance, an opportunity was lost to confront the MT (a lower cost treatment) with MRS and PCI in patients with multivessel CAD or LMCAL 8 .But based on the lack of advantage of DES over conventional stents (CS), in relation to death and AMI, it can be assumed that the PCI combined with DES would not bring any advantage over MT, except for a possible reduction in the need for anginaguided revascularization.Perhaps the ultimate answer to this question comes from the ECR ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches Trial) that will compare the effects of MT associated with revascularization plus isolated MT on death and AMI in patients with moderate to severe myocardial ischemia (<http://www.

clinicaltrials.gov> Identifier NCT01471522).
A proof of how MT evolved can be confirmed in the scenario of the stable CAD with severe left ventricular dysfunction.The STICH 9 study, hypothesis 1, showed that in five years of follow-up, mortality was similar in the confrontation between MT with MRS.Even with the limitations of this study, it was at least surprising the finding that MT produces the same life expectancy as MRS, revealing, therefore, that MT is a safe alternative for this type of pacient 9 .
Out of all the RCTs, the one that is closest to clinical reality, for having included the MT option, is the MASS II study 10 .This study, which addressed patients with multivessel CAD and preserved ventricular function, showed that MRS worked better than the PCI and CS combined and optimized MT in the protection against events composed of death, AMI and the need for anginaguided revascularization in a 10-year follow-up period.However, with regard to death, there was no significant difference between the three therapeutic options 10 .
Therefore, although there is no definitive answer as to the best therapeutic strategy for patients with multivessel stable CAD with or without left ventricular dysfunction, and under the perspective that "less is more", a proposal is made here that the optimized MT, a lower cost treatment, can be used without fear as the initial treatment of patients with multivessel stable CAD, as it does not account for mortality in excess, both in the presence and absence of left ventricular dysfunction compared with coronary revascularization techniques.

Potential Conflicts of Interest
No relevant conflicts of interest.

Sources of Funding
This study had no external funding sources.

Academic Association
This study is not associated to any graduate programs.

Point of View
The opinions expressed in this manuscript are those of the authors only.
The International Journal of Cardiovascular Sciences welcomes different points of view in order to stimulate discussions intended to improve patients' diagnosis and treatment.