Predictors and clinical implications of stent thrombosis in patients with ST-segment elevation myocardial infarction

Validity of the Stent Thrombosis Risk Score in Predicting Early Stent Thrombosis after Primary Percutaneous Coronary Intervention

Background

The thrombosis of the stent is one of the most important complications of percutaneous interventions, resulting in complete occlusion of the stented vessel. Aim of this study was to determine the validity of Stent Thrombosis Risk Score (STRS) in predicting early stent thrombosis (ST) after primary Percutaneous Coronary Intervention (PCI).

Methods

For this study, 569 consecutive patients undergone primary PCI from July 2018 to December 2018 were recruited. Early ST was defined as ST occurred during or within 30 days after the procedure. The STRS was calculated as proposed, developed, and validated in a past study. The receiver operating characteristic curve analysis was performed to determine the optimal cut-off value and area under the curve (AUC).

Results

A total of 569 patients were included, the median age was 56 [61-50] years. Early ST was observed in 33 (5.8%) patients. The median STRS was 4 [5-3] vs. 3 [4-2]; p = 0.009 for patients with and without Early ST respectively. STRS was found to be an independent predictor of early ST with an adjusted odds ratio of 1.41 (1.02-1.95). AUC was 0.631 and the optimal cut-off value was ≥5. Early ST rate was 3.3% at STRS of 0-2, which raised to 5.0% at STR of 3-4, and 17.2% at STRS of ≥5.

Conclusions

In conclusion, STRS was found to be an independent predictor of early ST after primary PCI and has significant discriminating power. The rate of early stent thrombosis after primary PCI exponentially increased at STRS cut-off value of ≥5.

Case report: intravascular ultrasound sonography-guided re-entry technique in crushed stent

Background

Stent thrombosis (ST) is a rare, but potentially fatal complication. Procedural problems, such as stent under-dimension/under-expansion or dual antiplatelet drug resistance may result into ST. These conditions are more frequent during primary percutaneous coronary intervention for ST-elevation myocardial infarction (STEMI).

Case summary

A 60-year-old male patient presented to our hospital with an inferior STEMI. In the emergency department, a dual antiplatelet therapy was administered with ticagrelor 180 mg and aspirin 250 mg IV. During the observation, the patient experienced a ventricular fibrillation. Urgent coronary angiography showed an occlusion of the proximal right coronary artery. Thrombus aspiration was performed followed by implantation of one drug-eluting stent. After 45 min early ST occurred and was treated by immediate thrombus aspiration and post-dilatation. Intravascular ultrasound sonography (IVUS) showed severe strut malapposition due to a partial crush after post-dilatation. Since it was not possible to directly insert the first guidewire in the stent lumen, the IVUS probe was placed between the vessel wall and the crushed stent to guide the manoeuvre.

Discussion

Crushed stent is a rare complication, being caused by an incorrect passage of the guidewire between the stent’s struts and the vessel wall in case of severe underexpansion. In this case, an IVUS-guided re-entry could be an option to gain the stent true lumen and avoid a second stent implantation.

Role of ST-Segment Resolution in Patients With ST-Segment Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention (from the 5-Year Outcomes of the EXAMINATION [Evaluation of the Xience-V Stent in Acute Myocardial Infarction] Trial)

In patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (pPCI), lack of ST-segment resolution (STR) is associated with poor prognosis at short- and long-term follow-up. The aim of this study was to evaluate the role of STR on very long-term outcomes in patients with STEMI treated with pPCI included in the EXAMINATION (Evaluation of the Xience-V Stent in Acute Myocardial Infarction) trial. Patients were stratified according to the presence of STR < 50% and STR < 70% at the 30-minute post-pPCI electrocardiogram. Primary end point was the patient-oriented composite endpoint (POCE) of all-cause death, any myocardial infarction, or any revascularization at 5-year follow-up. Both baseline and post-PCI 30-minute electrocardiograms were available for STR assessment in 1,351 patients. Of these patients, 228 (16.9%) and 500 (37.0%) exhibited STR < 50% and STR < 70%, respectively. At 5-year follow-up, the POCE was observed more frequently in patients with STR < 50% (hazard ratio [HR] 1.556; 95% confidence interval [CI] 1.194 to 2.027; p <0.001) and in patients with STR < 70% (HR 1.460, 95% CI 1.169 to 1.824, p <0.001) compared with patients with STR > 50% and STR ≥ 70%, respectively. In both cases, this difference was mainly driven by a significant increase in the rate of all-cause death and any revascularization. After multivariable adjustment, STR < 70%, but not STR < 50%, resulted as a 5-year independent predictor of POCE (adjusted HR 1.338, 95% CI 1.008 to 1.778, p = 0.044). In conclusion, in patients with STEMI, the evaluation of 70% STR after pPCI provides independent prognostic information at 5-year follow-up and it can be used to identify patients at high risk of very long-term cardiovascular events.

Influence of arterial hypotension on fractional flow reserve measurements

AIMS

To assess fractional flow reserve (FFR) variability in case of arterial hypotension in the clinical setting. FFR measurement is supposed to be independent of haemodynamics; there is, however, a strong relationship between trans-stenotic pressure variation and coronary flow. Non-clinical models suggest an inverse relationship between arterial pressure and FFR, but no clinical data have as yet confirmed this hypothesis.

METHODS AND RESULTS

In case of arterial hypotension (mean arterial pressure [Pa] ≤80 mmHg) during routine clinical FFR measurement (FFR1), a second measurement (FFR2) was performed after pressure normalisation by 0.5 mg IV phenylephrine. Fourteen intermediate chronic stenoses (%DS 58±21%, FFR1= 0.81±11) in 12 male patients showed 70±10 mmHg Pa at the time of measurement. After phenylephrine, Pa increased to 101±14 mmHg and FFR2 decreased to 0.75±12 (p<0.001) without heart rate variation. After Pa elevation, 40% of cases with FFR1 >0.80 changed to FFR2 ≤0.80.

CONCLUSIONS

In the present study, in case of arterial hypotension, FFR decreased with rising pressure. Whether repeated FFR measurement after haemodynamic normalisation is of clinical benefit remains at this point speculative and should be validated in a larger data set.

Predictors of adverse events among patients undergoing primary percutaneous coronary intervention: insights from a pooled analysis of the COMFORTABLE AMI and EXAMINATION trials

AIMS

The aim of this study was to identify predictors of adverse events among patients with ST-elevation myocardial infarction (STEMI) undergoing contemporary primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

Individual data of 2,655 patients from two primary PCI trials (EXAMINATION, N=1,504; COMFORTABLE AMI, N=1,161) with identical endpoint definitions and event adjudication were pooled. Predictors of all-cause death or any reinfarction and definite stent thrombosis (ST) and target lesion revascularisation (TLR) outcomes at one year were identified by multivariable Cox regression analysis. Killip class III or IV was the strongest predictor of all-cause death or any reinfarction (OR 5.11, 95% CI: 2.48-10.52), definite ST (OR 7.74, 95% CI: 2.87-20.93), and TLR (OR 2.88, 95% CI: 1.17-7.06). Impaired left ventricular ejection fraction (OR 4.77, 95% CI: 2.10-10.82), final TIMI flow 0-2 (OR 1.93, 95% CI: 1.05-3.54), arterial hypertension (OR 1.69, 95% CI: 1.11-2.59), age (OR 1.68, 95% CI: 1.41-2.01), and peak CK (OR 1.25, 95% CI: 1.02-1.54) were independent predictors of all-cause death or any reinfarction. Allocation to treatment with DES was an independent predictor of a lower risk of definite ST (OR 0.35, 95% CI: 0.16-0.74) and any TLR (OR 0.34, 95% CI: 0.21-0.54).

CONCLUSIONS

Killip class remains the strongest predictor of all-cause death or any reinfarction among STEMI patients undergoing primary PCI. DES use independently predicts a lower risk of TLR and definite ST compared with BMS. The COMFORTABLE AMI trial is registered at: http://www.clinicaltrials.gov/ct2/show/NCT00962416. The EXAMINATION trial is registered at: http://www.clinicaltrials.gov/ct2/show/NCT00828087.

Meta-analysis of randomized clinical trials comparing bivalirudin versus heparin plus glycoprotein IIb/IIIa inhibitors in patients undergoing percutaneous coronary intervention and in patients with ST-segment elevation myocardial infarction

This study sought to investigate the relative safety and efficacy of bivalirudin versus heparin plus glycoprotein (GP) IIb/IIIa inhibitors in patients undergoing percutaneous coronary intervention (PCI) and in those with ST-segment elevation myocardial infarction (STEMI). The safety of bivalirudin in PCI, particularly in patients with STEMI, continues to be debated. We searched the on-line databases for randomized controlled trials of bivalirudin versus heparin plus GP IIb/IIIa inhibitors. Data on study design, inclusion and exclusion criteria, sample characteristics, and clinical outcomes at 30 days were extracted. A total of 19,856 PCI patients included in 7 randomized trials and 5,820 patients with STEMI included in 2 randomized trials were separately analyzed. At 30 days, bivalirudin use in patients undergoing PCI resulted in similar rates of death, myocardial infarction, repeat revascularization, and stent thrombosis. In patients with STEMI, bivalirudin use resulted in decreased cardiac mortality (risk ratio [RR] 0.70, 95% confidence interval [CI] 0.50 to 0.97, p=0.03) compared with heparin plus GP IIb/IIIa inhibitors but an increase in definite stent thrombosis at 30 days (RR 1.88, 95% CI 1.09 to 3.24, p=0.02) driven by an increase in acute stent thrombosis (RR 5.48, 95% CI 2.30 to 13.07, p=0.0001). Bivalirudin use was associated with a decrease in Thrombolysis In Myocardial Infarction (TIMI) major (RR 0.58, 95% CI 0.46 to 0.74, p<0.0001) and TIMI minor (RR 0.55, 95% CI 0.48 to 0.63, p<0.0001) bleeding rates in PCI patients as well as in a subgroup of patients with STEMI. In conclusion, in PCI patients anticoagulation with bivalirudin results in similar ischemic adverse events and a reduction in TIMI major and minor bleeding at 30 days compared with heparin plus GP IIb/IIIa inhibitors. In patients with STEMI, bivalirudin use is associated with a reduction in TIMI major and minor bleeding and fewer deaths from cardiac causes but an increase in acute and 30-day definite stent thrombosis.

Comparison of newer-generation drug-eluting with bare-metal stents in patients with acute ST-segment elevation myocardial infarction: a pooled analysis of the EXAMINATION (clinical Evaluation of the Xience-V stent in Acute Myocardial INfArcTION) and COMFORTABLE-AMI (Comparison of Biolimus Eluted From an Erodible Stent Coating With Bare Metal Stents in Acute ST-Elevation Myocardial Infarction) trials

OBJECTIVES

This study sought to study the efficacy and safety of newer-generation drug-eluting stents (DES) compared with bare-metal stents (BMS) in an appropriately powered population of patients with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Among patients with STEMI, early generation DES improved efficacy but not safety compared with BMS. Newer-generation DES, everolimus-eluting stents, and biolimus A9-eluting stents, have been shown to improve clinical outcomes compared with early generation DES.

METHODS

Individual patient data for 2,665 STEMI patients enrolled in 2 large-scale randomized clinical trials comparing newer-generation DES with BMS were pooled: 1,326 patients received a newer-generation DES (everolimus-eluting stent or biolimus A9-eluting stent), whereas the remaining 1,329 patients received a BMS. Random-effects models were used to assess differences between the 2 groups for the device-oriented composite endpoint of cardiac death, target-vessel reinfarction, and target-lesion revascularization and the patient-oriented composite endpoint of all-cause death, any infarction, and any revascularization at 1 year.

RESULTS

Newer-generation DES substantially reduce the risk of the device-oriented composite endpoint compared with BMS at 1 year (relative risk [RR]: 0.58; 95% confidence interval [CI]: 0.43 to 0.79; p = 0.0004). Similarly, the risk of the patient-oriented composite endpoint was lower with newer-generation DES than BMS (RR: 0.78; 95% CI: 0.63 to 0.96; p = 0.02). Differences in favor of newer-generation DES were driven by both a lower risk of repeat revascularization of the target lesion (RR: 0.33; 95% CI: 0.20 to 0.52; p < 0.0001) and a lower risk of target-vessel infarction (RR: 0.36; 95% CI: 0.14 to 0.92; p = 0.03). Newer-generation DES also reduced the risk of definite stent thrombosis (RR: 0.35; 95% CI: 0.16 to 0.75; p = 0.006) compared with BMS.

CONCLUSIONS

Among patients with STEMI, newer-generation DES improve safety and efficacy compared with BMS throughout 1 year. It remains to be determined whether the differences in favor of newer-generation DES are sustained during long-term follow-up.