Regional Variation in Postoperative Myocardial Infarction in Patients Undergoing Vascular Surgery in the United States

Abstract

Background The aim of this study is to assess for regional variation in the incidence of post-operative myocardial infarction (POMI) following nonemergent vascular surgery across the United States to identify potential areas for quality improvement initiatives. Methods We evaluated POMI rates across 17 regional Vascular Quality Initiative (VQI) groups that comprised 243 centers with 1,343 surgeons who performed 75,057 vascular operations from 2010 to 2014. Four procedures were included in the analysis: carotid endarterectomy (CEA, n = 39,118), endovascular abdominal aortic aneurysm (AAA) repair (EVAR, n = 15,106), infrainguinal bypass (INFRA, n = 17,176), and open infrarenal AAA repair (OAAA, n = 3,657). POMI was categorized by the method of diagnosis as troponin-only or clinical/ECG and rates were investigated in regions with ≥100 consecutive cases. Regions with significantly different POMI rates were defined as those >1.5 interquartile lengths beyond the 75th percentile of the distribution. Risk-adjusted rates of POMI were assessed using the VQI Cardiac Risk Index all-procedures prediction model to compare the observed versus expected rates for each region. Results Overall rates of POMI varied by procedure type: CEA 0.8%, EVAR 1.1%, INFRA 2.7%, and OAAA 4.2% (P < 0.001). Significant variation in POMI rates was observed between regions, resulting in differing ranges of POMI rates for each procedure: CEA 0.5–2.0% (P = 0.001), EVAR 0.3–3.1% (P < 0.001), INFRA 1.1–4.8% (P < 0.001), and OAAA 2.2–10.0% (P < 0.001). A single region in 3 of the 4 procedure-specific datasets was identified as a statistical outlier with a significantly higher POMI rate after CEA, EVAR, and OAAA; this region was identical for the EVAR and OAAA datasets but was a different region for the CEA dataset. No significant variation in POMI was noted between regions after INFRA. Procedure-specific clinical POMI rates (mean; range) were significantly different between regions for EVAR (0.4%; 0–1.1%, P = 0.01) and INFRA (1.4%; 0.5–2.9%, P = 0.01), but not for CEA (0.4%; 0–0.8%, P = 0.53) or OAAA (1.6%; 0–3.8%, P = 0.23). Procedure-specific troponin-only POMI rates (mean; range) were significantly different between regions for all procedures: CEA (0.4%; 0.1–1.2%, P < 0.001), EVAR (0.7%; 0–2.1%, P < 0.001), INFRA (1.3%; 0.4–2.5%, P = 0.001), and OAAA (2.5%; 0–8.5%, P < 0.001). After risk adjustment, regional variation was again noted with 3 regions having higher and 4 regions having lower than expected rates of POMI. Conclusions Significant variation in POMI rates following major vascular surgery exists across VQI regions even after risk adjustment. These findings may present an opportunity for focused regional quality improvement efforts.

Factors associated with symptomatic postoperative myocardial infarction after endovascular aneurysm repair

“…In our study, we identified patient characteristics associated with a higher risk, including age older than 80 years, dialysis dependence, congestive heart failure, and dependent functional status. These results are similar to those of previous studies, [5][6][7]19,30 in which presence of serious medical comorbidities placed patients at greater risk for POMI after vascular surgery. Siracuse et al 19 also determined that ventilator dependency and emergency operation are associated with cardiac arrest requiring cardiopulmonary resuscitation.…”

Incidence and predictors of myocardial and kidney injury following endovascular aortic repair: a retrospective cohort study

“…25 In our study, the incidence of myocardial injury was almost twice as high. Also, the prevalence of myocardial infarction diagnosed according to the universal definition (6.7%) was higher in our study compared with previous studies-i.e., 5.1% in the EVAR-2 trial, and 1.1% in a study by Steely et al 26,27 This difference is likely explained by the absence of routine troponin screening in these studies and the use of highsensitivity troponin in a large proportion of our study population. Our cohort included consecutive patients, which likely included patients at higher risk than those who were included in these randomized-controlled trials.…”

Association of High Mortality With Postoperative Myocardial Infarction After Major Vascular Surgery Despite Use of Evidence-Based Therapies

“…This study has several limitations. The effect of regional variability, which has been associated with changes in POMI rates, could not be evaluated here . Given that the BMC2 database captures data within only 1 state (Michigan), we were unable to assess the potential effect this may have had.…”