Periprocedural MI as an Endpoint in Clinical Trials: A Proposed Path Forward

Mortality After Procedural or Spontaneous Myocardial Infarction

BACKGROUND

It remains unclear whether procedural myocardial infarction (pMI) and spontaneous myocardial infarction (spMI) have a similar impact on prognosis.

OBJECTIVES

The aim of this study was to assess mortality after pMI and spMI.

METHODS

Patients with chronic coronary syndrome (CCS) and baseline troponin ≤1× the upper reference level (URL) or with acute spMI who underwent percutaneous coronary intervention (PCI) were included. PMI was defined as post-PCI troponin increase >1× URL in patients with CCS. SpMI comprised any acute coronary syndrome with elevated troponin. The 1-year risk of all-cause death was assessed after pMI and spMI across 3 strata of troponin elevation (>1-5×, >5-35×, and >35× URL), with CCS patients having post-PCI troponin ≤1× URL as a reference group. Conventional troponin I was measured using the Architect methodology (Abbott).

RESULTS

Among 10,707 patients undergoing PCI from 2012 to 2020, 8,515 patients presented with CCS and 2,192 with spMI. Among CCS patients, 913 (10.7%) had pMI. Troponin peaks >1-5×, >5-35×, and >35× URL were observed in 53%, 41%, and 6% of patients with pMI, and in 24%, 38%, and 37% of patients with spMI, respectively. Mortality at 1 year was higher after pMI (7.7%; adjusted HR: 4.40; 95% CI: 1.59-12.2), and spMI (8.5%; adjusted HR: 7.57; 95% CI: 5.44-10.5) with troponin peak >35× URL compared with no-MI (1.4%). Mortality was also increased after spMI with troponin peak >1-5× or >5-35× URL.

CONCLUSIONS

Mortality at 1 year was significantly increased after pMI and spMI with troponin peak >35× URL, whereas for troponin levels ≤35× only spMI had a relevant impact on mortality.

Correlation Between Periprocedural Myocardial Infarction, Mortality, and Quality of Life in Coronary Revascularization Trials: A Meta-analysis

Background

The prognostic importance of periprocedural myocardial infarction (pMI) and its inclusion in the composite outcomes of coronary revascularization trials are controversial. We assessed whether pMI is a surrogate for all-cause or cardiac mortality and quality of life (QoL) outcomes in coronary revascularization trials.

Methods

All randomized trials comparing percutaneous coronary intervention vs coronary artery bypass grafting (MEDLINE, EMBASE, Cochrane Library) were identified. Trials were included if they reported data for pMI and mortality. Trial-level associations between pMI and all-cause or cardiac mortality and QoL were assessed using the coefficient of determination (R 2 ). The criterion for surrogacy was set at 0.7. Subgroup analyses based on pMI definition and on key clinical/procedural variables were performed.

Results

Twelve trials were included (11,549 patients; weighted mean follow-up: 5.6 years). There was a positive correlation between pMI and all-cause mortality (slope, 1.81; 95% CI, 1.00-2.63; R 2 = 0.72). In the trials that defined pMI as a rise in cardiac biomarkers >5 times the upper reference limit, pMI positively correlated with both all-cause (slope, 2.07; 95% CI, 1.00-3.14; R 2 = 0.93) and cardiac mortality (slope, 0.70; 95% CI, 0.20-1.19; R 2 = 0.87); no such relationships were present in trials that used a lower biomarker threshold. An inverse correlation was found between pMI and long-term changes in the Short Form Health Survey Physical Component score (slope, -4.66; 95% CI, -5.75 to -3.57; R 2 =0.99).

Conclusions

In the published coronary revascularization trials, pMI defined by larger biomarker elevations was associated with subsequent mortality and reduced QoL. These findings suggest that large pMI should be included as an outcome measure in coronary revascularization trials.

Current concepts in coronary artery revascularisation

Coronary artery revascularisation can be performed surgically or percutaneously. Surgery is associated with higher procedural risk and longer recovery than percutaneous interventions, but with long-term reduction of recurrent cardiac events. For many patients with obstructive coronary artery disease in need of revascularisation, surgical or percutaneous intervention is indicated on the basis of clinical and anatomical reasons or personal preferences. Medical therapy is a crucial accompaniment to coronary revascularisation, and data suggest that, in some subsets of patients, medical therapy alone might achieve similar results to coronary revascularisation. Most revascularisation data are based on prevalently White, non-elderly, male populations in high-income countries; robust data in women, older adults, and racial and other minorities, and from low-income and middle-income countries, are urgently needed.

Ischemia Trial: Does the Cardiology Community Need to Pivot or Continue Current Practices?

PURPOSE OF REVIEW

For decades, the standard of care for stable ischemic heart disease (SIHD) has been an ischemia-centric approach based on largely observational data suggesting a survival benefit of revascularization in patients with moderate-or-severe ischemia. In this article, we will objectively review the evolution of the ischemia paradigm, the trial evidence comparing revascularization to medical therapy in SIHD, and what contemporary practice should be in 2022.

RECENT FINDINGS

Randomized trials, including COURAGE and, most recently, the ISCHEMIA trial, have shown no reduction in "hard outcomes" like death and myocardial infarction (MI) in SIHD compared to medical therapy. The trial excluded high-risk patients with left main disease, low ejection fraction (EF) < 35%, and severe unacceptable angina. Irrespective of the severity of ischemia and the extent of coronary artery disease (CAD), revascularization did not offer any prognostic advantage over medical therapy. On the other hand, there was a durable improvement in symptoms. While there are many caveats to the ISCHEMIA trial, the overall strengths of the trial outweigh these limitations. The findings of ISCHEMIA are consistent with previous trials. It is time for the cardiology community to pivot towards medical therapy as the initial step for most patients with SIHD. Physicians should have the "COURAGE" to embrace "ISCHEMIA" and be comfortable with treating ischemia medically.