Upfront percutaneous coronary intervention versus conservative management in spontaneous coronary artery dissection: long-term outcomes from the Australian-New Zealand SCAD registry

Background Management of spontaneous coronary artery dissection (SCAD) is guided by clinical instability and angiographic severity in the absence of randomised data. The long-term impact of upfront percutaneous coronary intervention (PCI) in SCAD remains uncertain. Purpose To evaluate the use of upfront PCI, procedural success rates and long-term risk of major adverse cardiovascular events (MACE) following upfront PCI versus conservative management among patients with SCAD. Methods Patients with core laboratory–adjudicated SCAD enrolled in the Australian–New Zealand SCAD Registry1 (2009–2025) were analysed. PCI success was defined as residual stenosis <20% post- stent implantation or <50% post-balloon angioplasty, with achievement of thrombolysis in myocardial infarction (TIMI) flow grade 2 or 3. Angiographic improvement was defined as an increase of ≥1 TIMI flow grade. PCI-related complications were recorded. Predictors of PCI success were identified using logistic regression.The association between upfront PCI and MACE (all-cause death, recurrent MI, recurrent SCAD,unplanned revascularisation,stroke/TIA,or heart failure) was estimated using adjusted Cox proportional hazards models. Results Among 788 patients, 86 (10.9%) underwent upfront PCI and 702 (89.1%) were managed conservatively. PCI-treated patients had higher-risk presentations, including STEMI(73.0% vs 28.0%), cardiac arrest (8.2% vs 1.8%), left main SCAD(7.1% vs 0.6%), proximal SCAD (37.0% vs 10.0%), and baseline TIMI 0–1 flow (74.0% vs 19.0%) (all p<0.001)[Table 1]. PCI procedural success was achieved in 67.4% and angiographic improvement in 69.8%. Stent implantation was performed in 58.1%, balloon angioplasty in 43.0%, and cutting balloon angioplasty in 10.5%.PCI-related complications occurred in 39.5%, including propagation of dissection (82.4% of complications),slow flow/no-reflow (32.4%) and emergency CABG (2.9%). PCI failure occurred in 32.6%,most commonly due to inability to wire the true lumen(46.4%). Moderate-to-severe coronary tortuosity was independently associated with a lower likelihood of PCI success(adjusted OR 0.15, 95% CI 0.05–0.41). At 3 years, MACE occurred in 19.8%(17/86) of PCI-treated patients and 9.5%(67/702) of conservatively managed patients. In adjusted analysis, upfront PCI was associated with a twofold higher hazard of MACE; however, this did not reach statistical significance (adjusted HR 2.30, 95% CI:0.96–5.52; p=0.062)[Figure 1]. Conclusions In this large contemporary SCAD registry, patients selected for PCI represented a markedly higher-risk phenotype. PCI was associated with modest procedural success and a high complication rate, with coronary tortuosity strongly predicting PCI failure. While unadjusted MACE rates were higher among PCI-treated patients, there was no statistically significant association after adjustment. These findings highlight the complexity of revascularisation in SCAD and support careful patient selection strategies.Long term MACETable 1 PCI vs No PCI