Lennon, Ryan J.

Background— American College of Cardiology/American Heart Association guidelines recommend a door-to-balloon time (DTB) <90 minutes for nontransferred patients with ST-elevation myocardial infarction (STEMI) who undergo primary percutaneous coronary intervention. Systems of care to achieve and sustain this DTB performance over several years have not been previously reported. Methods and Results— The Mayo Clinic STEMI protocol was implemented in April 2004 and included activation of the cardiac catheterization laboratory by the emergency medicine physician; a single call system to activate the catheterization laboratory; catheterization laboratory staff arrival within 20 to 30 minutes of activation; and real-time performance feedback within 24 to 48 hours. Data were collected on nontransferred STEMI patients. The preimplementation group (June 2002 to March 2004) comprised 96 patients with a median DTB of 97 (interquartile range, 82, 130) minutes, and 40% had a DTB <90 minutes. The postimplementation group (May 2004 to March 2008) comprised 322 patients with a median DTB of 67 (interquartile range, 55, 82) minutes, and 81% had a DTB <90 minutes. Postimplementation DTB was significantly shorter than preimplementation DTB ( P <0.001). In the 4-year follow-up after protocol implementation, the DTB performance remained stable over time ( P =0.41). Conclusions— The Mayo Clinic STEMI protocol implemented strategies to reduce DTB for nontransferred patients with STEMI. DTB was significantly reduced, and the results were sustained over the 4-year follow-up period. Our experience demonstrates the effectiveness and durability of process changes targeting timeliness of primary percutaneous coronary intervention.

Background— Myonecrosis after percutaneous coronary intervention (PCI) has been correlated with a worse prognosis, but controversy exists about the clinical significance and potential mechanisms for the association. The aim of this study was to evaluate the relative impact of preprocedural and postprocedural cardiac troponin T (cTnT) levels on survival rate after PCI. Methods and Results— We evaluated 5487 patients from the Mayo Clinic registry who required nonemergency PCI, and we examined the relationship between periprocedural cTnT levels, with the 99th percentile cutoff value used for normal (<0.01 ng/mL), and outcomes. The patients were divided into 3 groups: normal preprocedural and postprocedural cTnT levels (no myonecrosis), normal preprocedural but elevated postprocedural cTnT levels (PCI-related myonecrosis), and abnormal preprocedural cTnT. The 30-day death rates were 0.1%, 0.6%, and 2.3%, respectively, in the 3 groups. In a multivariable model, an abnormal pre-PCI cTnT level (hazard ratio 9.66 [2.30–40.57]; P =0.002), and PCI-related myonecrosis (4.71 [1.02–21.83]; P =0.048) were independent predictors of 30-day mortality. Over a median follow-up of 28 months, an abnormal pre-PCI cTnT level (hazard ratio 1.79 [1.35–2.39]; P <0.001) independently predicted death, but the occurrence of PCI-related myonecrosis did not. A postprocedural elevation in creatine kinase MB fraction was not an independent predictor of long-term risk of death (0.912 [0.70–1.19]; P =0.5). Conclusions— A preprocedural cTnT level >0.01 is a powerful independent predictor of prognosis after PCI and is of greater prognostic significance than the postprocedural biomarker levels. PCI-related myonecrosis occurs frequently and predicts short-term but not long-term risk of death.

Background— Concern regarding risk of late thrombosis after “off-label” treatment with drug-eluting stents has prompted increased use of bare-metal stents (BMS) in current practice. The sequelae of late BMS failures, however, have been poorly characterized. Methods and Results— We performed a retrospective study of 4503 consecutive patients treated with at least 1 BMS and dual antiplatelet therapy between 1994 and 2000. The cumulative incidence of stent thrombosis was 0.5% at 30 days (95% CI, 0.3% to 0.7%), 0.8% at 1 year (95% CI, 0.6% to 1.1%), and 2.0% at 10 years (95% CI, 1.5% to 2.5%). Risk of late (30 days to 1 year) and very late (>1 year) BMS thrombosis was increased among patients considered off label for drug-eluting stent use ( P =0.024). When saphenous vein graft interventions were excluded, however, risk after off-label use was not significantly increased ( P =0.23). Other correlates included vein graft intervention, prior myocardial infarction (MI), peripheral vascular disease, and ulcerated lesion ( P <0.001). Mortality was markedly increased after late and very late BMS thrombosis, particularly during the first 30 days (hazard ratios, 22 [95% CI, 3.1 to 159] and 40 [95% CI, 15 to 107], respectively). The 10-year incidence of clinical restenosis was 18.1% (95% CI, 16.5% to 19.7%), presenting with MI in 2.1% (95% CI, 1.6% to 2.6%). Restenosis presenting with MI was associated with increased mortality compared with no restenosis (hazard ratio, 2.37; P <0.001) and with restenosis with a non-MI presentation (hazard ratio, 2.42; P <0.001). Conclusions— The incidence of BMS thrombosis and of MI caused by restenosis during extended follow-up is significant. Both complications are associated with mortality.

Background— Quality improvement efforts have focused on strategies to improve the timeliness of reperfusion therapy in ST-elevation myocardial infarction patients who present to hospitals with and without percutaneous coronary intervention (PCI) capability. We implemented and evaluated a protocol to optimize the timeliness of reperfusion therapy and to coordinate systems of care for a PCI center and 28 regional hospitals located up to 150 miles away across 3 states. Methods and Results— The present study focused on a prospective, observational cohort of 597 patients who presented with ST-segment elevation and within 12 hours of symptom onset to Saint Marys Hospital and 28 regional hospitals up to 150 miles away between May 2004 and December 2006. The Mayo Clinic ST-elevation myocardial infarction protocol implemented strategies to improve timeliness of reperfusion therapy and to coordinate systems of care for transfer between hospitals. The study sample consisted of 258 patients who presented to Saint Marys Hospital and were treated with primary PCI (group A), 105 patients who presented to a regional hospital with symptom onset >3 hours and then were transferred for primary PCI (group B), and 131 patients who presented to a regional hospital with symptom onset <3 hours and were treated with full-dose fibrinolytic therapy (group C). For groups A and B, median door-to-balloon times were 71 and 116 minutes, respectively. Door-to-balloon time <90 minutes was achieved in 75% of group A and 12% of group B. Median door-to-needle time was 25 minutes for group C, and 70% had door-to-needle time <30 minutes. Conclusions— The Mayo Clinic ST-elevation myocardial infarction protocol demonstrates the feasibility of implementing strategies to optimize the timeliness of reperfusion therapy and the times that can be achieved through coordinated systems of care for ST-elevation myocardial infarction patients presenting to a PCI center (Saint Marys Hospital) and 28 regional hospitals without PCI capability located up to 150 miles away across 3 states.

The objective of this study was to assess the usefulness of a comparison of clinical failure and restenosis rates of endovascular procedures at 1 year in patients with peripheral arterial disease. The resulting comparison is presented as “clinical failure/restenosis coordinate.” The authors screened 171 papers describing the outcome of lower extremity angioplasty or stent placement. In 20 of them, authors reported detailed outcomes of interest, including baseline demographic measurements, location of arterial occlusive lesions, a measure of restenosis (measured by ankle-brachial indices, ultrasonography, or angiography), and clinical outcomes (mortality, repeat percutaneous transluminal angioplasty, or amputation). An overview of these 20 angioplasty papers was performed. Besides the usual meta-analyses of each end point separately, data were also plotted as coordinates of clinical failure versus restenosis. The clinical failure-to-restenosis coordinate was calculated and reported for percutaneous transluminal angioplasty of the aortoiliac and femoropopliteal distributions. Clinically reported outcomes in the literature were used to calculate the clinical failure/restenosis coordinate. This value was significantly different for various locations of the angioplasty and various baseline angiographic characteristics. A numeric coordinate pair of clinical failure and restenosis is identifiable in patients undergoing endovascular treatment of peripheral arterial disease. The varying coordinates may be important in elucidating the incidence and mechanisms of clinical failure after endovascular treatment. The coordinate reported in this article is hypothesis-generating about mechanisms of endovascular treatment failure. This coordinate is important in determining the role of restenosis in the clinical failure of endovascular therapy of peripheral arterial disease.

Background— Little is known about the impact of technological and pharmacological advances on long-term outcome after percutaneous coronary intervention in general clinical practice. Methods and Results— We analyzed in-hospital and long-term outcome of 24 410 percutaneous coronary interventions among 18 575 unique patients who underwent percutaneous coronary intervention at Mayo Clinic over 25 years. The study population was divided into group 1 (n=3708), coronary interventions from 1979 to 1989; group 2 (n=7020), interventions from 1990 to 1996; group 3 (n=10 952), interventions from 1996 to 2003; and group 4 (n=2730), interventions from 2003 to 2004. Despite the fact that patients in groups 3 and 4 were significantly older, sicker, and had greater prevalence of comorbid conditions, heart failure, and previous revascularization than those in groups 1 and 2, procedural success in groups 3 and 4 improved significantly (94%) versus groups 2 (89%) and 1 (78%) ( P <0.001). Significant reduction in in-hospital mortality (groups 4 to 1: 1.8%, 1.7%, 2.6%, 3.0%; P <0.001) and need for emergency bypass surgery (groups 4 to 1: 0.4%, 0.5%, 1.6%, 5%; P <0.001) was noted in groups 3 and 4 compared with groups 1 and 2. Better adherence to currently recommended evidence-based medications for secondary prevention was seen in the recent time periods. After adjustment, significant reduction in follow-up mortality (hazard ratio, 0.81 and 0.74 for groups 3 and 4, respectively); death or myocardial infarction (hazard ratio, 0.80 and 0.75 for groups 3 and 4, respectively); death, myocardial infarction, or revascularization (hazard ratio, 0.76 and 0.58 for groups 3 and 4, respectively) was noted in recent time periods. Conclusions— Despite higher-risk profiles of patients who underwent percutaneous coronary intervention in recent time periods, procedural success as well as in-hospital and long-term outcomes improved significantly over the last 25 years.

Background— In patients with coronary artery disease (CAD), acute thrombosis frequently occurs in coronary arteries with only mild or moderate stenoses. Obesity increases the risk of atherosclerosis, but it is not known whether it also increases the risk of coronary thrombosis. We hypothesized that body mass index (BMI) might be an independent predictor of an acute coronary syndrome in patients with established coronary atherosclerosis. Methods and Results— Of 504 patients undergoing coronary angiography, those with evidence of >10% coronary artery stenoses were divided into 2 groups, with either stable (n=226) or unstable CAD (unstable angina or myocardial infarction; n=156). After adjusting for other risk factors (age, gender, blood pressure, lipid levels, insulin resistance, leptin, fibrinogen, C-reactive protein (CRP), CAD severity on angiography, smoking status, and a history of myocardial infarction or hypertension), BMI had a significant independent association with an acute coronary syndrome, with an odds ratio of 1.49 ( P =0.014). This positive relation between BMI and the risk of acute coronary events was evident for even mildly elevated BMI values. Multivariate analysis also showed that CRP and the number of coronary lesions were independent predictors of risk of an acute coronary event. Conclusions— In patients with established coronary atherosclerosis, BMI, as well as CRP and number of coronary lesions, are independently associated with acute coronary syndromes. There is evidence of increased risk even at mildly elevated BMI levels.