Interventional studies presented at ACC.23/WCC provide insights into the safety and efficacy of minimally invasive mitral valve repair, longer-term results with transcatheter edge-to-edge repair (TEER) for patients with severe secondary mitral regurgitation (MR) as well as in low surgical risk aortic stenosis treated with transcatheter rather than surgical aortic valve replacement (TAVR, SAVR), along with findings on immediate vs. staged complete PCI revascularization and using intravascular imaging vs. angiography guidance in PCI.

Findings from the UK MINI MITRAL trial, presented by Enoch Akowuah, MD, showed that in patients undergoing minimally invasive and conventional surgical techniques for mitral valve repair there was a similar improvement in physical activity, surgical outcomes and quality of life.

The study included 330 patients (average age 67, 30% women) with severe degenerative MR treated at 10 centers in the U.K. and randomized to mitral valve repair by either sternotomy (n=163) or mini-thoracotomy (n=166).

The study's primary endpoint, the change in physical function and ability to return to work from baseline at 12 weeks, was not significantly different between groups. Researchers noted that at six weeks patients in the mini-thoracotomy group had recovered physical function whereas the sternotomy group had not.

Looking at secondary endpoints, a second operation because of bleeding was needed for one patient in the mini-thoracotomy group and four patients in the sternotomy group. The length of hospital stay was shorter in the mini-thoracotomy group than the sternotomy group (median five days vs. six days).

"The study has also answered two key questions about the mini-thoracotomy approach – the valve repair rate and the quality and durability of valve repair performed using this approach," Akowuah said. "Valve repair rates were excellent [at 96%] and similar with those obtained with sternotomy. Moreover, at one year after surgery more than 92% of patients in both groups had no or mild valve leakage."

The five-year data from the COAPT trial, presented by Gregg W. Stone, MD, FACC, and simultaneously published in the New England Journal of Medicine, showed that TEER for patients with severe secondary MR was safe, cut the rate of hospitalizations for heart failure (HHF) and reduced all-cause deaths.

In COAPT, 614 patients (average age 72, 36% women), 302 were randomized to TEER using a MitraClip plus medical therapy (device group) and 312 to medical therapy alone (control group). Participants had left ventricular (LV) failure, severe MR and symptoms of HF despite best medical therapy at the time.

The primary effectiveness endpoint was all HHF within two years of follow-up. After five years, death or HHF occurred in 73.6% in the TEER group and 91.5% in the control group. The annualized rate of HHF through five years was 33.1% per year for TEER and 57.2% per year for control. Overall, TEER was associated with a 28% risk reduction in all-cause mortality.

"MitraClip made a profound difference for patients with [HF] and severe MR. Based on these findings, appropriate patients should be treated with MitraClip as early as possible," Stone said. "However, nearly three in four patients still died or were hospitalized for [HF] within five years, even after successful MitraClip, because treating the regurgitant mitral valve does not improve their underlying [LV] dysfunction," said Stone. "We need to develop better therapies for advanced [HF] if the prognosis of this high-risk patient population is to be further improved."

The three-year outcomes from the EVOLUT Low Risk trial, presented by John K. Forrest, MD, FACC, and simultaneously published in JACC, found that rates of death and disabling stroke were lower among patients with aortic stenosis and a low surgical risk treated with TAVR vs. SAVR.

The study included 1,414 attempted implants (730 TAVR; 684 SAVR). Patients in the international trial (median age 74, 35% women), all had severe symptomatic aortic stenosis and a low surgical risk.

The primary endpoint was a combination of all-cause death or disabling stroke. After three years, 7.4% of TAVR patients experienced the primary endpoint vs. 10.4% of surgical patients (hazard ratio [HR], 0.70; p=0.051), with the difference between treatment arms remaining broadly consistent over time: –1.8% at year one; –2.0% at year two; –2.9% at year three.

With SAVR vs. TAVR, the rates were significantly lower for mild paravalvular regurgitation (2.5% vs. 20.3%) and pacemaker placement (9.1% vs. 23.2%). Valve hemodynamics were significantly improved with TAVR vs. SAVR (mean gradient 9.1 mm Hg vs. 12.1 mm Hg for SAVR; p<0.001) at three years.

"The consistent benefit of TAVR at three years provides further evidence that TAVR deserves to be the dominant treatment modality for patients with aortic stenosis undergoing valve replacement," said Forrest.

The BIOVASC trial, presented by Roberto Diletti, MD, PhD, and simultaneously published in Lancet, found that immediate complete revascularization by PCI was as safe and effective in treating multivessel heart disease as staged treatment in patients presenting with a STEMI or NSTEMI acute coronary syndrome.

A total of 1,525 patients (median age 65, 78% male) from four European countries were randomized in the noninferiority trial to either immediate complete revascularization (n=764) or staged complete revascularization (n=761). The primary outcome was the composite of all-cause mortality, myocardial infarction (MI), any unplanned ischemia-driven revascularization, or cerebrovascular events at one year following the index procedure.

Among 1,506 patients at the one-year follow-up, 7.6% of patients in the immediate treatment group had a primary endpoint event vs. 9.4% in the staged group (HR, 0.78; p for noninferiority=0.0011). No between-group difference was seen for all-cause death (1.9% vs. 1.2%, respectively). More than twice as many patients in the staged group had a second MI (4.5% vs. 1.9%; HR, 0.41; p=0.0045), and more unplanned ischemia-driven revascularizations were performed in the staged vs. immediate revascularization group (6.7% vs. 4.2%).

"Immediate complete treatment offered reassurance that patients would not suffer a second heart attack while waiting for their second procedure," said Diletti.

The RENOVATE-COMPLEX-PCI trial, presented by Joo-Yong Hahn, MD, PhD, and simultaneously published in the New England Journal of Medicine, showed that PCI guided by intravascular imaging vs. angiography in patients with complex coronary artery disease was associated with a lower risk of death due to cardiac causes, target vessel-related MI, or need for target vessel revascularization (TVR).

A total of 1,639 patients in South Korea were randomized to undergo either intravascular imaging-guided PCI (n=1,092) or angiography-guided PCI (n=547). The primary endpoint was a composite of death from cardiac causes, target vessel-related MI, or clinically driven TVR.

With a median follow-up of 2.1 years, the primary endpoint was observed in 7.7% of patients in the intravascular imaging group and 12.3% in the angiography group (HR, 0.64; p=0.008). Looking at the component endpoints, in the intravascular imaging group vs. the angiography group, respectively, cardiac death occurred in 1.7% and 3.8% patients; target vessel-related MI in 3.7% and 5.6%; and clinically driven TVR in 3.4% and 5.5%. No between-group difference was seen for safety events.

"The results of our trial may lead to an increase in the use of intravascular imaging – and, in turn, an improvement in clinical outcomes – among patients with complex coronary blockages who are undergoing stenting," said Hahn.

Clinical Topics: Acute Coronary Syndromes, Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Atherosclerotic Disease (CAD/PAD), Aortic Surgery, Cardiac Surgery and Heart Failure, Cardiac Surgery and VHD, Acute Heart Failure, Interventions and ACS, Interventions and Coronary Artery Disease, Interventions and Imaging, Interventions and Structural Heart Disease, Angiography, Nuclear Imaging, Mitral Regurgitation

Keywords: ACC Annual Scientific Session, ACC23, Acute Coronary Syndrome, Aortic Valve, Aortic Valve Stenosis, Angiography, Cardiac Surgical Procedures, Coronary Artery Disease, Diagnostic Imaging, Heart Failure, Heart Valve Prosthesis, Mitral Valve, Mitral Valve Insufficiency, Percutaneous Coronary Intervention, Sternotomy, ACC.23/WCC Meeting Newspaper, ACC Scientific Session Newspaper

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