Better outcomes with invasive strategy if anatomic complete revascularisation is possible

In patients with chronic coronary disease, better long-term outcomes may be achieved using an invasive approach over a conservative approach when anatomic complete revascularisation (ACR) is achievable [1]. These were the findings of a sub-analysis of the ISCHEMIA trial.

Many observational studies have shown that complete revascularisation (CR; encompassing both ACR and ischaemic, or functional complete revascularisation [FCR]) following percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) procedures is associated with fewer subsequent major adverse cardiac events (MACE) than incomplete revascularisation (IR) [1,2]. However, this association is not always found, and few studies have adjusted for differences in baseline clinical and anatomic covariates [1,2]. Evidence was also lacking on the impact of CR on patients receiving an invasive versus a conservative management strategy. This was the motivation for a pre-planned sub-analysis of the ISCHEMIA trial (NCT01471522), which was presented by Dr Gregg Stone (Mount Sinai Medical Centre, NY, USA).

Previously published results from the ISCHEMIA trial (n=5,179) found no evidence that the use of an initially invasive strategy reduced the risk of ischaemic cardiovascular events or death from any cause when compared with an initially conservative strategy (optimal medical therapy alone) [3]. The current ISCHEMIA sub-study had 2 objectives: (1) to compare the outcomes of ACR and FCR with IR in patients who underwent an initially invasive strategy, and (2) to examine the impact that CR may have had in those patients who underwent an initially invasive strategy compared with an initially conservative strategy.

To satisfy the first objective, angiographic core laboratory assessments were conducted on 2,296 patients to determine the degree of completeness of revascularisation following PCI and CABG. Among patients in the invasive strategy arm, 1,802 had achieved ACR versus anatomic IR (a CR rate of 43.3%), and 1,743 had achieved FCR versus functional IR (a CR rate of 58.3%). In the ACR group, revascularisation had been achieved by PCI in 72.3%, CABG in 26.4%, and a hybrid approach in 1.3% of cases (see Figure 1). In the FCR group, revascularisation was achieved by PCI in 71.6%, CABG in 27.0%, and a hybrid approach in 1.4% of cases. Clinical predictors of completeness of revascularisation were anatomic, including the number of chronic total occlusions, the number of diseased vessels and lesions, and SYNTAX score. Multivariable analysis showed that CABG was associated with a higher rate of CR than PCI.

Figure 1: Completeness of revascularisation in patients using an invasive strategy [1]



ACR, anatomic complete revascularisation; CABG, coronary artery bypass graft; FCR, functional complete revascularisation; PCI, percutaneous coronary intervention.

Comparing the impact of complete versus incomplete revascularisation on the primary endpoint of cardiovascular death, myocardial infarction, hospitalisation for cardiac arrest, heart failure, or unstable angina, the adjusted hazard ratio in the ACR group was 0.79 (95% CI 0.55–1.15; P=0.22), while in the FCR group it was 0.96 (95% CI 0.68–1.34; P=0.80).

To fulfil the secondary objective, all 2,296 patients who had undergone an initially invasive strategy were compared with the 2,498 patients who had been treated conservatively, using an inverse probability weighted analysis. Overall rates of revascularisation were similar to those observed in the first group; 43.6% had achieved ACR, and 58.5% had achieved FCR (see Figure 2). Comparing primary outcomes in the ACR showed an overall 3.5% difference, favouring the invasively managed group over the conservatively managed group; this effect was somewhat smaller in the FCR group, showing an overall 2.3% difference, also favouring the invasively managed group. The overall results from the ISCHEMIA trial show a 2.5% difference, favouring the invasively managed group over the conservatively managed group.

 

Figure 2: Completeness of revascularisation in patients treated using an invasive strategy versus a conservative strategy [1]



ACR, anatomic complete revascularisation; CABG, coronary artery bypass graft; FCR, functional complete revascularisation; PCI, percutaneous coronary intervention.

The researchers cautioned that these results represent associations and not necessarily causality; however, they also concluded that these results suggest that in patients with chronic coronary syndrome, better outcomes may be achieved with an invasive approach over a conservative approach if ACR can be achieved. For this reason, the likelihood of safely achieving ACR should be considered when choosing the treatment strategy for patients in this population.

1. 
   
   1. Stone GW. Impact of completeness of revascularization on clinical outcomes in patients with stable ischaemic heart disease treated with an invasive versus conservative strategy: the ISCHAEMIA trial. ACC 2021 Scientific Session, 15–17 May 2021.
   2. Gaba P, et al. Nat Rev Cardiol. 2021;18:155–168.
   3. Maron DJ, et al. N Engl J Med 2020;382:1395–1407.

 

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Posted on 9 July 202131 January 2024