NIRS-IVUS to Improve Assessment of Coronary Artery Disease Severity in Patients Referred for Transcatheter Aortic Valve Implantation

The aim of the IMPACTavi prospective cohort study is to test feasibility and safety of clinically indicated intravascular coronary imaging with NIRS-IVUS in addition to routine coronary angiography in patients scheduled for TAVI, to improve assessment of CAD severity in this challenging group of patients.

Concomitant coronary artery disease (CAD) is frequent in patients referred for transcatheter aortic valve replacement (TAVI) and there is evidence for a subsequent prognostic impairment. Percutaneous coronary intervention (PCI) is believed to improve prognosis in selected cases, which is why current guidelines recommend PCI to be considered in case of coronary artery diameter stenosis \> 70% in proximal segments. Beyond those cases, selection is hampered by inherent shortcoming of the assessment of CAD severity by angiography alone as well as clinical and complex hemodynamic interactions between both pathologies. In patients with CAD alone, the FDA-cleared near-infrared spectroscopy and intravascular imaging (NIRS-IVUS) dual imaging catheter (Indfraredx, Inc., Bedford, USA) has proven the ability to reliably measure lipid plaque burden as well as to identify patients and plaques at increased risk for future adverse cardiovascular events. NIRS-IVUS imaging offers the unique possibility to improve angiographic CAD severity assessment in patients referred for TAVI, avoiding the influence of hemodynamic interactions and pathophysiological overlap between CAD and severe AS.

The IMPACTavi trial is designed as a prospective, non-randomized cohort study to investigate whether NIRS-IVUS-derived lesion characteristics will allow identification of patients likely to suffer adverse clinical events during clinical follow-up after TAVI. Patients with severe aortic stenosis will be qualified for enrollment if routine coronary angiography during diagnostic workup before TAVI shows evidence of coronary artery disease with at least one native vessel without prior stent implantation and at least one lesion requiring NIRS-IVUS imaging for clinical indications, and if at 30mm of total NIRS-IVUS pullback length in sufficient quality for offline analysis have been obtained. Clinical indication, technique and timing of PCI and TAVI will be at the discretion of the interdisciplinary heart-team. The primary and secondary endpoints will be assessed during clinical follow-up out to 24 months. Findings from NIRS-IVUS imaging will be analyzed on a patient- and lesion-level, in order to evaluate correlations of high- vs. low-risk lesion characteristics to the incidence of patient- and lesion-level MACE.

Eligibility Criteria:
Inclusion Criteria:

1. Age ≥ 18 years and able to give consent
2. Severe aortic stenosis found eligible for transfemoral TAVI by the multi-disciplinary heart team
3. Angiographic evidence of coronary artery disease with absence of coronary stents in at least one native coronary artery
4. At least 30 mm of total NIRS-IVUS pullback length in sufficient quality for offline analysis of at least one native coronary artery with absence of coronary stents, containing at least one lesion requiring NIRS-IVUS imaging for clinical indications
5. Written, informed consent by the patient or her/his legally-authorized representative for participation in the study
6. In women with childbearing potential a negative pregnancy test is mandatory

Exclusion Criteria:

1. Age \< 18years
2. Any clinical contraindications to perform NIRS-IVUS
3. ST-elevation myocardial infarction or cardiogenic shock within 48h prior to enrollment
4. Decompensated aortic valve stenosis requiring emergency TAVI
5. History of coronary artery bypass graft (CABG)
6. Severe renal failure with estimated glomerular filtration rate \<20 ml/min
7. Malignancies or other comorbid conditions (resulting in a life expectancy \<12 months)
8. Inability to fully cooperate with the study protocol
9. Known allergy towards P2Y12 receptor antagonists
10. Pregnancy