Conservative Management Should be First Line Therapy for SCAD ESC 2018: Canadian SCAD study

Spontaneous coronary artery dissection (SCAD) is an underdiagnosed, poorly misunderstood condition. The predisposing causes and management of this condition are still unclear. To throw light on this, the CANADIAN SCAD cohort study was a large, prospective, multicenter, observational, natural history study that enrolled 750 non-atherosclerotic SCAD patients from 22 centers (20 from Canada and 2 from the US). The key study objective was the analysis of cardiovascular outcomes within the hospital and long-term. Secondary outcomes included the assessment of clinical and angiographic characteristics of patients presenting with SCAD.

In the study, the investigators found that the majority of the patients were treated conservatively (86% of patients). Of these patients, subsequently, only 2.3% required revascularization in the hospital. Despite conservative therapy in the majority of patients, acute in-hospital and 30-day survival was good with an in-hospital mortality rate of 0.1% and no further deaths up to 30 days. Further, the results showed that cardiovascular complications were not infrequent. At 30 days, the overall MAE rate including mortality, recurrent MI, unplanned revascularization, heart failure, stroke, and TIA was 8.8%. This implied that patients would require close monitoring after hospital discharge at 30 days. The rate of other presentations for a cardiac visit to the Emergency Room was 4.9%. Half of these patients required admission for chest pain. Additionally, peripartum SCAD and connective tissue disorder were found to be independent predictors of 30-day MACE.

When asked about the clinical implications of the study, Dr. Jacqueline Saw, recipient of an inaugural Advancing Women’s Heart Health research grant from Heart & Stroke Foundation, remarked “Our study supports the fact that first-line therapy for SCAD should be conservative management and PCI should be limited to patients at high risk with ongoing chest pain, ischemia, or patients who are hemodynamically unstable such as those with cardiogenic shock, ventricular tachycardia, ventricular fibrillation and left main dissection.” This is reflected by the results that show that out of the 100 patients in the study that underwent PCI, rates of unsuccessful PCI was 30%, thereby highlighting the challenges of PCI with this condition.

Dr. Saw also acknowledged the major limitation of the study was that being an observational study, it involved capturing in the real world what physicians were doing for this challenging cohort of patients. However, all patients with SCAD in these institutions may not have been captured due to its difficult diagnosis. Patients may have been missed if they were not picked up on angiogram or died before hospital presentation.