ACC.26 Recap: 6 Practice-Changing Trials to Know

The American College of Cardiology (ACC) Scientific Sessions 2026 saw the presentation of a slew of major, practice-changing studies and trials. Between fractional flow reserve (FFR) angiography in patients with coronary artery disease (CAD) from the ALL-RISE trial to mavacamten’s positive efficacy data in adolescent patients with obstructive hypertrophic cardiomyopathy (oHCM), major data was presented for just about every major disease state in cardiology.

In light of the sheer volume of new research, the editorial team at HCPLive has collected 6 of the most practice-changing results from ACC.26. Catch up on any major study data you may have missed during the conference below:

FFR Angiography Noninferior to Pressure-Wire Strategy in CAD Analysis, With William Fearon, MD

Presented by William Fearon, MD, professor of medicine and director of interventional cardiology at Stanford, the ALL-RISE study proved the noninferiority of angiography-guided FFR compared to a pressure-wire-guided strategy in patients with CAD. Enrolling a total of 1930 patients, the trial demonstrated a 98.5% success rate for FFR angiography compared to a 98.6% success rate for pressure-wire-based measurements. The mean time to calculate the assessment was 6 minutes in the FFRangio group and 8 in the pressure-wire group.

SCOUT-HCM: Mavacamten Outperforms Placebo in Adolescents With HCM, With Joseph Rossano, MD, MS

Mavacamten successfully demonstrated greater reductions in left ventricular outflow compared to placebo in adolescent patients with oHCM in the SCOUT-HCM trial. Joseph Rossano, MD, MS, co-director of the Cardiac Center at the Children’s Hospital of Philadelphia, presented the data at ACC.26, demonstrating the drug’s efficacy among 44 patients. Mean Valsalva left ventricular outflow tract gradient ultimately decreased by 48.5 mmHg in the mavacamten arm compared to -0.5 mmHg in the placebo arm, and Rossano and colleagues ultimately reported few significant adverse events.

Ultrasound-Facilitated Catheter-Directed Fibrinolysis Reduces Early Decompensation in Pulmonary Embolism

The HI-PEITHO study, investigating ultrasound-facilitated, catheter-directed fibrinolysis with anticoagulation in patients with acute, intermediate-risk pulmonary embolism (PE), has demonstrated the system’s superiority to anticoagulation alone. Among 544 patients, this catheter intervention substantially reduced the risk of early clinical deterioration – a combination outcome of incidence of PE-related death, cardiorespiratory decompensation or collapse, and symptomatic PE recurrence within 7 days occurred in 11 patients in the intervention arm compared to 28 in the control group.

CHAMPION-AF: Left Atrial Appendage Closure Noninferior to NOACs

The CHAMPION-AF trial demonstrated the noninferiority of device-based left atrial appendage closure (LAAC) compared to non-vitamin K antagonist oral anticoagulant (NOAC) therapy in preventing adverse events in patients with atrial fibrillation (AF). The trial enrolled 3000 patients with non-valvular AF at elevated stroke risk, who were then randomized to either the Watchman FIx device or an approved NOAC. Ultimately, a composite primary efficacy endpoint cardiovascular death, stroke, or systemic embolism occurred in 81 patients among the device group and 65 in the NOAC group, resulting in a difference of 0.9 percentage points.

Don't Miss a Beat: MRA Updates at ACC 2026 Scientific Sessions

SPIRIT-HF ultimately showed that spironolactone did not significantly reduce a composite endpoint of heart failure hospitalization and cardiovascular death compared to placebo in patients with heart failure with preserved ejection fraction (HFpEF) or mildly reduced ejection fraction (HFmrEF). In actuality, patients administered spironolactone saw an increase in hospitalizations and severe adverse events, potentially raising questions about the safety of the drug in HFpEF and HFmrEF. However, investigators noted high discontinuation due to the COVID-19 pandemic, potentially influencing the study’s capacity to conclusively demonstrate differences between the groups.

IVUS-CHIP: IVUS-Guided PCI Fails to Demonstrate Superiority in Complex Coronary Arteries

Among 2020 patients with complex coronary arteries, randomly assigned in a 1:1 ratio to either IVUS-guided PCI or angiography-guided PCI, target-vessel failure occurred in 14% of patients in the IVUS arm compared to 11% in the angiography arm. The trial failed to demonstrate IVUS-guided PCI’s superiority to angiography, with complications occurring in 11.3% of the IVUS group and 10.2% of the angiography group. Investigators ultimately declared that the industry is not currently capable of leveraging intravascular imaging data to guide PCI in a manner that justifies the increased complexity and cost of the procedure.