To the Editor,

In 2016, the Canadian Cardiovascular Society (CCS) released clinical practice guidelines1 for the perioperative cardiovascular management of patients undergoing non-cardiac surgery. These new guidelines represented a significant departure from other widely used guidelines2,3 in that biomarkers, specifically brain natriuretic peptide (BNP) or N-terminal-pro hormone BNP (NT-proBNP), were strongly recommended for both cardiac risk assessment and monitoring for myocardial injury after non-cardiac surgery (MINS). The Department of Anesthesia at St. Paul’s Hospital (SPH) in Vancouver, BC, a tertiary academic acute care hospital, was an early adopter of the CCS guidelines and implemented a local MINS protocol in January 2017.

Successful implementation of the MINS protocol requires appropriate patient identification, followed by protocol activation and completion for all eligible cases throughout the entire perioperative course. One year following our MINS protocol implementation, we sought to determine the rate of adherence for protocol activation and completion at SPH. We aimed to determine the baseline adherence rates for elective and emergency surgeries and hypothesized that the use of bundled interventions would improve adherence rates.

The study was a quality improvement project and did not require institutional ethics approval. The pre-intervention phase was from 1 September to 30 November 2017 (at least six months following initial MINS protocol implementation, with three consecutive months of data collection that avoided the summer and winter holiday-related reductions in operating room scheduling). The bundled interventions that were introduced throughout March 2018 are listed in the Table. The post-intervention phase was from 1 April to 30 June 2018. All data were collected retrospectively by three anesthesiologists using the operating room administration records and the hospital’s digital charting system. The availability of preoperative NT-proBNP and appropriate ordering of postoperative troponins for eligible patients were used to define adherence to protocol activation and completion, respectively. Rates of adherence were compared using Fisher’s Exact test.

Table Perioperative bundled interventions used to improve rates of adherence for MINS protocol activation and completion in elective and emergency surgeries
Full size table

A total of 2,430 surgical cases were assessed during the pre-intervention (n = 1,166) and post-intervention periods (n = 1,264); 46.6% (1132/2430) of patients met the criteria for MINS protocol activation. The baseline adherence for eligible patients undergoing elective surgeries requiring hospital admission was 68.1% (254/373) for protocol activation and 25.0% (55/220) for protocol completion; implementing the bundled interventions improved these adherence values to 81.3% (339/417; P < 0.001) and 43.1% (79/183; P = 0.001), respectively. At baseline, 254 patients had NT-proBNP levels drawn, 62 (24.4%) of which were positive. This was similar to 23.6% (80/335) in the post-intervention period. For emergency surgeries, only baseline protocol completion was assessed and there was a significant improvement after the bundled interventions (11.9% vs 34.1%; P < 0.001).

During the study period, we found that almost one in two patients undergoing non-cardiac surgery requiring admission at SPH qualified for monitoring using the MINS protocol as per the 2016 CCS guidelines. For elective surgeries, preoperative NT-proBNP values had been measured in most eligible patients who started the protocol, often during pre-admission assessment; however, very few eligible patients completed the required daily troponin measurements. The low protocol completion rate was also seen in emergency surgeries. In both elective and emergency cases, protocol adherence rates improved significantly with bundled interventions. The bundled interventions have now become part of the permanent clinical workflow at our hospital, and ensure follow-up with the division of general internal medicine for patients who have suffered MINS. We hope our study provides a resource for other departments seeking to implement the MINS protocol.