Rationale and design of the MASS COMM trial: A randomized trial to compare percutaneous coronary intervention between MASSachusetts hospitals with cardiac surgery on-site and COMMunity hospitals without cardiac surgery on-site

Nonemergency PCI at hospitals with or without on-site cardiac surgery

BACKGROUND

Emergency surgery has become a rare event after percutaneous coronary intervention (PCI). Whether having cardiac-surgery services available on-site is essential for ensuring the best possible outcomes during and after PCI remains uncertain.

METHODS

We enrolled patients with indications for nonemergency PCI who presented at hospitals in Massachusetts without on-site cardiac surgery and randomly assigned these patients, in a 3:1 ratio, to undergo PCI at that hospital or at a partner hospital that had cardiac surgery services available. A total of 10 hospitals without on-site cardiac surgery and 7 with on-site cardiac surgery participated. The coprimary end points were the rates of major adverse cardiac events--a composite of death, myocardial infarction, repeat revascularization, or stroke--at 30 days (safety end point) and at 12 months (effectiveness end point). The primary end points were analyzed according to the intention-to-treat principle and were tested with the use of multiplicative noninferiority margins of 1.5 (for safety) and 1.3 (for effectiveness).

RESULTS

A total of 3691 patients were randomly assigned to undergo PCI at a hospital without on-site cardiac surgery (2774 patients) or at a hospital with on-site cardiac surgery (917 patients). The rates of major adverse cardiac events were 9.5% in hospitals without on-site cardiac surgery and 9.4% in hospitals with on-site cardiac surgery at 30 days (relative risk, 1.00; 95% one-sided upper confidence limit, 1.22; P<0.001 for noninferiority) and 17.3% and 17.8%, respectively, at 12 months (relative risk, 0.98; 95% one-sided upper confidence limit, 1.13; P<0.001 for noninferiority). The rates of death, myocardial infarction, repeat revascularization, and stroke (the components of the primary end point) did not differ significantly between the groups at either time point.

CONCLUSIONS

Nonemergency PCI procedures performed at hospitals in Massachusetts without on-site surgical services were noninferior to procedures performed at hospitals with on-site surgical services with respect to the 30-day and 1-year rates of clinical events. (Funded by the participating hospitals without on-site cardiac surgery; MASS COM ClinicalTrials.gov number, NCT01116882.).

Current state of the performance of percutaneous coronary intervention in centres without on-site cardiac surgery

Before the routine use of coronary stents, potential complications of percutaneous coronary interventions required the presence of backup cardiac surgery on-site. Advances in pharmacotherapy and interventional techniques, particularly in the last decade, have significantly decreased the rates of complications requiring emergency cardiac surgery, from approximately 4% to 6% in the balloon angioplasty era to as low as 0.3% to 0.6% in the contemporary era of routine intracoronary stent implantation. An early invasive approach has been shown to improve outcomes among patients with non-ST elevation acute coronary syndromes (NSTEACS), particularly in those at the highest risk, emphasising the importance of early access to revascularisation premises in such patients. Patients with ST-segment elevation myocardial infarction require immediate and sustained recanalisation of the culprit vessel to obtain rapid reperfusion of the threatened myocardium, in order to reduce infarct size and improve outcomes. Primary percutaneous coronary intervention at hospitals without on-site cardiac surgery improves clinical outcomes and reduces length of stay when compared with fibrinolytic therapy. It also significantly reduces door-to-balloon times when compared with transfer for percutaneous coronary interventions at hospitals with on-site surgery. It has been published that risk-adjusted mortality rates for patients undergoing percutaneous coronary interventions in centres without on-site surgical backup are comparable with those of percutaneous coronary intervention facilities that have cardiac surgery on-site, regardless of whether percutaneous coronary intervention was performed as primary therapy for ST-segment elevation myocardial infarction or in a non-primary setting. To achieve these results however, an adequate percutaneous coronary intervention programme is required, including proper hospital infrastructure and appropriately trained interventional cardiologists.