# Impact of myocardial perfusion abnormalities on clinical outcomes in patients treated with percutaneous coronary intervention for chronic total occlusions

## TL;DR

This study found that significant heart perfusion issues before CTO-PCI treatment do not increase mortality or major cardiovascular events, but may reduce long-term angina hospitalizations.

## Contribution

The novel contribution is demonstrating that pre-PCI perfusion abnormalities do not worsen clinical outcomes after CTO-PCI, challenging prior assumptions.

## Key findings

- Moderate–severe ischaemia on MPI did not increase all-cause mortality after CTO-PCI.
- MACCE risk was similar between groups at both 90 days and 5 years.
- Patients with moderate–severe ischaemia had lower 5-year angina hospitalization risk.

## Abstract

Myocardial perfusion imaging (MPI) is used to evaluate ischaemia in patients with chronic total occlusion (CTO), but its prognostic implications following percutaneous coronary intervention (PCI) of CTO remain uncertain.

To evaluate outcomes in patients treated with CTO-PCI stratified by moderate–severe ischaemia on MPI prior to intervention.

Patients from the Western Danish Heart Registry assessed by nuclear MPI and subsequently treated with CTO-PCI ≤ 6 months were included. Moderate–severe ischaemia was defined as ≥10% left ventricle involvement. Primary endpoints were all-cause mortality and a composite of major adverse cardio- and cerebrovascular events [MACCE; cardiovascular death, myocardial infarction (MI), stroke, and hospitalization for heart failure (HF) or angina pectoris]. Secondary endpoints included the individual MACCE components. Outcomes were compared between patients with and without moderate–severe ischaemia using multivariable Cox regression and competing risk regression at 90-day and 5-year follow-ups. Among 319 patients, 208 (65.2%) had moderate–severe ischaemia. All-cause mortality was similar between patients with and without moderate–severe ischaemia [adjusted hazard ratio (aHR) 1.12, 95% confidence interval (CI): 0.52–2.43], P = 0.77). The estimated risk of MACCE was comparable between groups at 90 days [aHR 0.76 (0.38–1.55), P = 0.46] and 5 years [aHR 0.74 (0.45–1.20), P = 0.22]. No difference was found in MI [5 years: aHR 0.76 (0.26–2.22), P = 0.61] or hospitalization for HF [90 days: aHR 0.44 (0.16–1.21), P = 0.11]; 5 years: aHR 0.62 (0.30–1.30), P = 0.21]. Hospitalization for angina was similar at 90 days [aHR 0.75 (0.26–2.16), P = 0.60], but a decreased 5-year risk was observed in patients with moderate–severe ischaemia [aHR 0.46 (0.23–0.91), P = 0.026].

Moderate–severe ischaemia on nuclear MPI was not associated with differences in mortality or MACCE after CTO-PCI but was associated with a lower long-term risk of angina hospitalization.

Graphical Abstract