Spontaneous Coronary Artery Dissection - AntipLatelet Therapy Intensity in Guided coNservative Management (SCAD-ALIGN) Trial

Spontaneous coronary artery dissection (SCAD) is a rare cause of acute coronary syndrome in which blood flow to the heart muscle is reduced or interrupted. It predominantly affects women between 30 and 55 years of age and typically occurs in the absence of atherosclerosis. For many years, SCAD remained underdiagnosed and has only recently been more systematically recognised. The SCAD-ALIGN trial will be the first randomised study to systematically compare two antiplatelet treatment strategies in patients with SCAD.

SCAD is usually not associated with significant atherosclerosis or the classic vessel occlusion caused by a blood clot. Instead, bleeding occurs within the wall of a coronary artery, causing the vessel layers to separate and thereby impairing or completely obstructing blood flow. Patients develop symptoms of acute myocardial infarction, such as chest pain, shortness of breath, or nausea. A characteristic feature is that these symptoms often occur in individuals without a prior history or risk of heart disease.

Platelets play a crucial role in blood clotting but can also accumulate inside blood vessels and further impair flow. Antiplatelet medications are used to prevent this. In current clinical practice, SCAD patients are often treated according to general guidelines for acute coronary syndrome, which typically include two different antiplatelet therapies, a strategy developed and tested in older patients with proven atherosclerosis.

The SCAD-ALIGN trial is based on a fundamental difference between SCAD and classic heart attacks. In typical heart attacks, a blood clot usually blocks a vessel, and after the implantation of a vascular support device ("stent"), intensive antiplatelet therapy is used to prevent further clot formation. In SCAD, however, the underlying problem is a tear or bleeding within the vessel wall. In this situation, intensive antiplatelet therapy could delay the resolution of the bleeding or even worsen it, thereby adversely affecting the course of the disease. The study will therefore investigate whether a less intensive treatment strategy may be more beneficial in these patients.

The SCAD-ALIGN trial compares two treatment strategies: moderate antiplatelet therapy with a single medication for three months versus more intensive therapy with two agents for three months, followed by nine months of treatment with a single medication. The primary endpoint is a composite of recurrent myocardial ischemia, recurrent SCAD, myocardial infarction, the need for revascularization, and death.

The SCAD-ALIGN trial is part of the Multinational Clinical Trials Initiative of the Global Cardiovascular Research Funders Forum (GCRFF). The study is designed as an international, multicentre, randomised, open-label clinical trial. Because SCAD is a rare condition, close collaboration across national borders is essential. The results are expected to make an important contribution to the development of evidence-based treatment recommendations for SCAD, improve care and quality of life for patients worldwide.