Early revascularization for patients with spontaneous coronary artery dissection (SCAD) involving the left main coronary artery (LM) improves outcomes for these high-risk patients versus medical therapy in a new pooled analysis of published cases. The study — published Monday online ahead of print in the JACC: Cardiovascular Interventions — is of "major value" in plugging an "important knowledge gap" in the scant knowledge surrounding LM SCAD overall, cardiologists wrote in an accompanying editorial. SCAD overall is an uncommon cause of myocardial infarction (MI), according to the study's authors, led by Michele Morosato, MD, from Vita-Salute San Raffaele University, Milan, and Carlo Gaspardone, MD, from the IRCCS San Raffaele Scientific Institute, Milan. LM SCAD in particular is rare, and known to be life-threatening, though minimal data have been reported. The researchers therefore set out to investigate clinical features, contemporary management strategies and clinical outcomes of 132 patients with LM SCAD whose data were documented across 1,106 papers in MEDLINE and Embase databases between 1990 and 2023. Invasive vs conservative The mean age of the patients was 40 years and 80% were womenThe patients were divided according to the original treatment approach used, with those receiving initial medical therapy assigned to the 'conservative strategy' group (53 patients, 40%) and those given initial revascularization through percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) assigned to the 'invasive strategy' group (79 patients, 60%). Of the invasive strategy group, 48 (61%) successfully underwent CABG and 31 (39%) underwent PCI, although this was only successful in 25 patients (81%). Crossover from a conservative strategy to an invasive management was observed in 22 of the 53 patients (42%). Of these, 13 (59%) underwent CABG and 9 (41%) underwent PCI. Those treated with a conservative approach were more frequently women (89% vs 73%; P = 0.033), and were younger (38 years vs 42 years; P = 0.022). Overall, 38 patients (29%) were hemodynamically unstable at presentation, with cardiogenic shock in 30 cases (22%). The invasive management approach was slightly more common in hemodynamically unstable patients as a whole (32% vs 25%; P = 0.376) but was significantly more common in those with cardiogenic shock (28% vs 15%; P = 0.056) and flow-limiting dissection (90% vs 51%; P < 0.001). Significant morbidity and mortality risk At the 120-day median follow-up endpoint, the primary composite endpoint of all-cause death, left ventricular assist device implantation, heart transplantation, recurrent MI and urgent myocardial revascularization occurred in 32% of the LM SCAD patients overall. Individually, the endpoint components rates overall were 9% for all-cause death; 13% for recurrent MI; 22% for urgent myocardial revascularization and 4% of patients underwent left ventricular assist device implantation or heart transplantation. The risk of the primary composite endpoint was significantly lower in in the invasive strategy group, occurring for 13 patients compared to the conservative management group, in which 27 patients suffered the outcome (adjusted hazard ratio [HR]: 0.37; 95% confidence interval [CI]: 0.20-0.69; P<0.001). The authors went on to note that the lower incidence of early adverse outcomes in the invasive group was driven largely by reduction in recurrent MI (1.3% in invasive management vs 30% in conservative; HR: 0.07; 95% CI: 0.02-0.31; P<0.001) and urgent MR (8.9% vs 42% respectively; HR: 0.19; 95% CI: 0.08-0.45; P<0.001). Hemodynamic factor The lower endpoint rates seen in the invasive group came irrespective of patients' initial hemodynamic status (P for interaction = 0.640), the authors added, noting that the benefit of invasive strategy was evident in hemodynamically stable patients (HR: 0.24; 95% CI: 0.10-0.60; P = 0.002) and a trend toward a lower incidence of the primary endpoint was seen in hemodynamically unstable patients treated invasively (HR: 0.40; 95% CI: 0.15-1.09; P = 0.075). Patients undergoing CABG had a lower incidence still of the primary endpoint compared with those treated with PCI (HR: 0.16; 95% CI: 0.04-0.59; P = 0.005), driven mainly by patients in stable condition (CABG vs PCI: HR: 0.18; 95% CI: 0.04-0.98; P = 0.04), the authors added. In an accompanying manuscript, editorialists led by Fernando Alfonso, MD, from Universidad Autónoma Madrid, Spain, pointed out that: "The superiority of CABG over PCI was mainly seen among [hemodynamically] stable patients, suggesting that a stable scenario may be better suited for optimal surgical results, whereas both revascularization strategies were associated with similar outcomes among unstable patients, a situation in which PCI can be more readily implemented." Hypothesis-generating The authors concluded that the "hypothesis-generating data" in the study as a whole should be confirmed in future prospective registries and clinical trials. The editorialists hailed the study for helping to address the knowledge gap in "this elusive clinical entity". However, they highlighted some key issues, including that publication bias appears "very likely, and this might underestimate adverse event rates and overestimate procedural success, potentially favoring the interventional approach.” They added that missing information over the precise revascularization strategy, and the devices used, would also be helpful to inform revascularization strategies. "The optimal medical management of patients with SCAD remains controversial. Betablockers and antiplatelet agents are frequently used in clinical practice, but only randomized clinical trials will be able to determine their potential role in this condition," they concluded. Sources: Morosato M, Gaspardone C, Romagnolo D, et al. Left Main Spontaneous Coronary Artery Dissection: Clinical Features, Management, and Outcomes. JACC: Cardiovasc Interv 2025; DOI:10.1016/j.jcin.2025.01.427. Alfonso F, de Val D, Bastante T. Left Main Spontaneous Coronary Artery Dissection: Insights on a Dreadful Presentation. JACC: Carduiovasc Interv 2025; DOI:10.1016/j.jcin.2025.03.003. Image Credit: Malik E/peopleimages.com – stock.adobe.com