7.1 Current Role of Hemodynamic Support in Complex, High-Risk PCI

These proceedings summarize the educational activity of the 16th Biennial Meeting of the International Andreas Gruentzig Society held January 31-February 3, 2022 in Punta Cana, Dominican Republic

Faculty Disclosures     Vendor Acknowledgments

2022 IAGS Summary Document

Statement of the problem or issue

In recent years there has been a steady increase in the complexity of patients undergoing PCI, both in terms of their coronary anatomy as well as their comorbidities and overall risk profiles. Use of mechanical circulatory support (MCS) for high-risk PCI remains an important but controversial topic. The challenges are multiple, including the basic concepts of when might MCS be needed, that is, what complex coronary anatomy poses greatest risk of hemodynamic compromise, what are the potential benefits of MCS, what type of circulatory support should be used, and which patient populations should be considered for it. At the present time, the 2 major MCS support systems in common use are the intra-aortic balloon pump (IABP) and the Impella device.

Gaps in knowledge

Data for use of MCS in high-risk PCI are limited, but clinical trials are ongoing and these will help better understand and define patients who may derive benefit from hemodynamic support. The BCIS-1 trial¹ compared elective IABP with no IABP in 301 patients (mean LVEF 23% and Jeopardy score ≥8-12). There was no difference in major adverse events (MACCE) at hospital discharge between the 2 groups (15.2% vs 16%; P=.85). Mortality at 6 months was numerically lower in the IABP group but did not reach significance (4.6 vs 7.4%; P=.32) However, viability of jeopardized myocardium distal to target lesions was not assessed. The PROTECT II trial² randomized 448 pts to IABP or Impella 2.5 during elective high-risk PCI. Inclusion criteria were complex multivessel, unprotected left main or last remaining artery, and LVEF ≤30%-35% (mean LVEF of enrolled patients  24%). There were no differences in major adverse events (MAEs) at 30 and 90 days between the 2 groups in the intention-to-treat analysis. Interestingly, the per-protocol analysis showed significant reduction in MAE at 90 days in favor of Impella (40% vs 51%; P=.023). A significant “learning curve” was observed for use of Impella 2.5 for MCS. Additionally, rotational atherectomy (RA) was performed more often in the Impella arm (14.2% vs 9%; P=.083), possibly due to enhanced hemodynamic support, but this led to more post-PCI cardiac biomarker rise. In patients without RA use, MCS with Impella was associated with fewer MAEs at 90 days (35.5% vs 50.5%; P=.003). Unfortunately, this trial was terminated early at an interim analysis so conclusions must be tempered. PROTECT III and RESTORE EF were prospective, multicenter, single-arm post-market-approval studies of Impella in high-risk, nonemergency PCI. Final results of both were presented at the TCT conference in November 2021. In PROTECT III, authors focused on those patients who would have qualified for the PROTECT II randomized trial (PII-like), and compared them with the PROTECT II patients. The PII-like patients in PROTECT III were more “complex” than those in PROTECT II, RA was employed more often, complete revascularization was achieved more often, and there was less bleeding requiring transfusion. MACCE at 90 days was 15.2% in PROTECT III vs 21.9% in PROTECT II (P=.037). In RESTORE EF, the primary outcome comparator was LVEF at 90 days, which improved significantly: mean 35% at baseline to mean 45% at 90 days; P<.001). It is suggested that more complete revascularization in the Impella-supported patients led to this improvement. Additional details on PROTECT III and RESTORE EF await their full publication. While data at present are encouraging for MCS use in high-risk PCI patients in general, and for Impella rather than IABP in particular, many barriers remain. Cost and availability are 2—for example, IABP is less expensive, more widely available, and requires less training and support to operate the device; on the other hand, Impella is more expensive, less widely available, and requires more training and support to operate the device. Another barrier-gap is patient selection: how and with what tools can we assess “high risk?” Importantly, just recently, researchers in the United Kingdom analyzed the BCIS interventional database from 2006-2016, and developed a proposed “CHIP score” for assessing patient risk.³ The score ranges from 0 to 13. Cumulative MACCE was 0.6% with CHIP score of 0, rising to 4.4% with CHIP score ≥5, and much higher beyond that. More widespread investigation of the utility of this score is awaited.

Possible solutions and future directions

The PROTECT IV trial (NCT04763200) is currently enrolling patients into a prospective, multicenter, randomized, parallel-controlled, open-label, 2-arm study. Eligible high-risk patients are randomly assigned to Impella-supported PCI or to standard PCI with or without IABP support. Estimated completion date for enrollment is 2024, with follow-up completed in 2026. Results should help further refine the concept of high risk, whether MCS can be beneficial in high-risk PCI, and which of the 2 devices being compared in the 2 arms might be superior.

References

1. Perera D, Stables R, Thomas M, et al. Elective intra-aortic balloon counterpulsation during high-risk percutaneous coronary intervention: a randomized controlled trial. JAMA. 2010;304(8):867-874. doi:10.1001/jama.2010.1190

2. O’Neill WW, Kleiman NS, Moses J, et al. A prospective, randomized clinical trial of hemodynamic support with Impella 2.5 versus intra-aortic balloon pump in patients undergoing high-risk percutaneous coronary intervention: the PROTECT II study. Circulation. 2012;126(14):1717-1727. doi:10.1161/CIRCULATIONAHA.112.098194

3. Protty M, Sharp ASP, Gallagher S, et al. Defining percutaneous coronary intervention complexity and risk: an analysis of the United Kingdom BCIS Database 2006-2016. JACC Cardiovasc Interv. 2022;15(1):39-49. doi:10.1016/j.jcin.2021.09.039