Initial Invasive or Conservative Strategy for Stable Coronary Disease. N Engl J Med (2020)

Take Home Message

  • Through cohort dilution, transfers from one strategy to another, and CABG underutilization, the ISCHEMIA trial -- if misinterpreted or overgeneralized -- may inappropriately put into question the indications for CABG that have been shown to improve survival, freedom from MI, and symptoms beyond other modalities.
  • El estudio ISCHEMIA puede ser interpretado en forma equivocada sino consideramos que el grupo de pacientes fue muy heterogéneo, con una alta incidencia de transferencia de pacientes desde una estrategia terapéutica hacia otra, con una baja utilización de la cirugía coronaria como método de revascularización. Es sabido que la cirugía coronaria, es superior a otras alternativas terapéuticas para el tratamiento de la enfermedad coronaria brindando una mejor sobrevida alejada con una mejor calidad de vida y  una menor incidencia de síntomas y de infarto de miocardio.


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Commentary by Daniel Navia, MD

The study included more than 5000 pts with positive stress test, with Ct angiogram for rule out LMD (Left Main Disease) and confirm at least one vessel disease. Mean follow-up 3 years 41% DBT patients. Mild angina SAQ (Seattle Angina Questionary) scale: 1 or three episode per month and 1/3 of the patients no angina in the last month. Conservative therapy (CON) needs 28% of cardiac Cath and also patients with CON need 23 % cross-over to revascularization (PCI: 74% and CABG  26%). Study was negative for difference between groups. Conclusions: unstable angina patients with no LMD without symptoms lifestyle limiting there is no need to revascularize. Patients with symptoms lifestyle limiting NEED revascularization (PCI vs CABG??). An early increased risk for primary outcome events in the invasive- strategy group was attributable to more procedural infarctions in early follow-up. Patients in the invasive strategy subsequently had fewer spontaneous MIs. The incidence of death from any cause was low and similar in the two groups. ISCHEMIA therefore concluded that among patients with stable ischemic heart disease (SIHD) who had moderate or severe ischemia on stress testing, an initial invasive strategy, compared to an initial conservative strategy, did not reduce the rates of major adverse cardiac events. In our view CABG -- the only treatment known to surpass OMT in preventing death and MI in SIHD -- was underutilized in ISCHEMIA, as is often the case worldwide. Despite some misinterpretations, the ISCHEMIA trial did not investigate whether revascularization is better than optimal medical therapy, but rather compared 2 initial treatment strategies. CABG -- the only treatment known to surpass OMT in preventing death and MI in SIHD -- was underutilized in ISCHEMIA, Strikingly, there were more patients in the invasive-strategy group who received no revascularization (i.e., 534) than patients who underwent CABG (i.e., 530). Why was CABG, the only intervention known as better than OMT, rarely used in ISCHEMIA despite 2/3 of patients having multivessel CAD and 42% having diabetes? The ISCHEMIA trial in my opinion, reinforces the notion that CABG surgeons should be experts at understanding all stages of myocardial revascularization trials, from their rationale, design, conduct and interpretation, to their applicability. Cardiac surgeons should thoroughly understand the indications for CABG, as well as the indications for PCI and for OMT alone, particularly in the context of SIHD. The latest results from the FREEDOM, NOBLE and EXCEL trials, as well as in patients with severely reduced LV ejection fraction, support that an indication for CABG should be ruled out in every ‘ISCHEMIA-type’ patient.