High risks associated with surgical revascularization in patients with left ventricular (LV) dysfunction call for more data on percutaneous coronary intervention (PCI) as a potential alternative strategy.
At TCTAP 2022, Divaka Perera, MD(Guy’s & St Thomas’ Hospital and King’s College, London, UK) hinted at the upcoming REVIVED-BCIS2 trial to address prevailing questions on PCI as a routine revascularization strategy in LV dysfunction (LVD).
“Studies on LVD have shown that coronary artery bypass graft (CABG) reduces mortality and morbidity at high procedural cost,” he said at the virtual conference on Apr 27. “And in certain populations, it takes years after surgery for benefits to outweigh the hits.”
“As a procedure with fewer procedural risks, whether PCI can offer similar benefits to surgery without high costs is still unknown,” he added. “But the 2-year follow-up results of the upcoming trial on routine PCI for LVD patients may answer long-standing questions.”
REVIVED-BCIS2 is a randomized controlled trial (RCT) that examines whether PCI can improve event-free survival compared to optimal medical therapy (OMT) alone in 700 patients with impaired LV function and myocardial viability at 35 centers across the UK.
Previously, studies like the randomized controlled STICHES trial, which extended the mortality data of the STICH trial, showed better survival outcomes with CABG over OMT at 10-years for patients with left ventricular ejection fraction (LVEF) ≤35% (HR 0.84, 95% CI, 0.73- 0.97, p=0.02).
However, the early and high risks associated with CABG – coupled with lacking data on PCI versus OMT – have made revascularization for acute and chronic LVD a near “evidence-free zone” that forces most decisions on individual clinical variables.
‘More evidence needed for staged non-culprit PCI in patients with acute LVD, cardiogenic shock’
Perera noted that although several studies showed multivessel PCI did more harm than good for patients with acute LVD and cardiogenic shock, the benefits and risks of staged, non-culprit PCI needs more study.
“Current guidelines do not recommend routine multivessel PCI during the index procedure, but the safety and efficacy of staged PCI are unknown,” he said. “We’re careful about interpreting existing observational studies, and we need RCT data.”
The 2019 European guidance on cardiogenic shock complicating myocardial infarction stresses early angiography and identifying culprit lesions eligible for revascularization with PCI or CABG.
Most European recommendations also favor surgical revascularization based on the SHOCK trial that showed a survival benefit with any revascularization at 6-months.
The guidance gave a Class III recommendation to PCI, advising against the procedure based on the CULPRIT-SHOCK trial for complex patients with acute MI, cardiogenic shock and multivessel disease (MVD).
CULPRIT-SHOCK found patients who received PCI for the infarct-related lesion only (with optional staged revascularization for nonculprit-lesions) had a lower 30-day mortality risk than those who received immediate multivessel PCI (0.84, 95% CI, 0.72-0.98, P=0.03).
“Studies have shown that multivessel PCI was detrimental for complex patients, and the detriment was prominent in the first 30-days,” Perera said. “But the safety and efficacy of staged non-culprit PCI are unknown.”
“We need more than just observational data, but the problem with RCTs and cardiogenic shock is that patients are hard to recruit. Several trials like DanGer Shock, EURO-SHOCK and ECLS-SHOCK are underway, but they are struggling to complete.”
‘Subpar results with CABG in chronic LVD raise question of PCI’
In patients with chronic severe LVD and stable coronary artery disease (CAD), previous lukewarm results with CABG have swiveled attention to the potential of PCI.
STITCH investigators first tried to address problems of revascularization in chronic, severe LVD and stable CAD with a randomized trial in 2011.
Results showed the endpoint of all-cause mortality or cardiovascular hospitalization at 5-years favored CABG over OMT (58% vs. 68%, HR 0.74, 95% CI, 0.64-0.85, P<0.001); however, CABG also had an increased early risk of all-cause mortality.
“Unfortunately, the early excess mortality associated with surgery indicated no benefit at 5-years (0.46 vs. 0.41; HR 0.86, 0.72-1.04, p=0.123 and, in some cases, it took nearly 10-years for the benefits to outweigh the upfront risk,” Perera said. “And the 50%-range for mortality risk was not a great outcome, making PCI an obvious pertinent question.”
Despite the theoretical benefits of PCI, several studies like EXCEL showed PCI had similar outcomes to surgical revascularization. PCI was also “not without risk,” although the impact on LVEF is unknown.
Considering the dearth of studies comparing PCI and OMT in the population, REVIVED-BCIS2 investigators rolled out the first randomized comparison of PCI and OMT versus OMT alone in 700 patients with severe LV dysfunction (EF ≤35%), heart failure (HF) symptoms (NHYA I-IV), extensive coronary disease and viable myocardium.
The trial, which followed patients for nearly two years after randomization, designated the primary endpoint as event-free survival, comprised of all-cause mortality or HF hospitalization. The study is slated for completion by March and presentation at the upcoming European Society of Cardiology Congress (ESC 2022), Perara said.