Early unfractionated heparin treatment in patients with STEMI - trial design and rationale.

The early unfractionated heparin (UFH) treatment in patients with ST-elevation myocardial infarction (STEMI) is a single-center, open-label, randomized controlled trial. The study population are patients with STEMI that undergo primary percutaneous coronary intervention (PPCI). The trial was designed to investigate whether early administration of unfractionated heparin immediately after diagnosis of STEMI is beneficial in terms of patency of infarct-related coronary artery (IRA) when compared to established UFH administration at the time of coronary intervention. The patients will be randomized in 1:1 fashion in one of the two groups. The primary efficacy endpoint of the study is Thrombolysis in myocardial infarction (TIMI) flow grades 2 and 3 on diagnostic coronary angiography. Secondary outcome measures are: TIMI flow after PPCI, progression to cardiogenic shock, 30-day mortality, ST-segment resolution, highest Troponin I and Troponin I values at 24 hours. The safety outcome is bleeding complications. The study of early heparin administration in patients with STEMI will address whether pretreatment with UFH can increase the rate of spontaneous reperfusion of infarct-related coronary artery.

Coronary features across the spectrum of out-of-hospital cardiac arrest with ST-elevation myocardial infarction (CAD-OHCA study).

AIM: We hypothesized that adult patients with out-of-hospital cardiac arrest (OHCA) and ST-elevation myocardial infarction (STEMI) requiring prolonged resuscitation have more severe coronary artery disease (CAD) than those responding rapidly, and more severe CAD than patients with STEMI without OHCA. METHODS: Consecutive conscious and comatose OHCA patients with STEMI after reestablishment of spontaneous circulation (ROSC), and patients with refractory OHCA undergoing veno-arterial extracorporeal membrane oxygenation (E-CPR OHCA) were compared to STEMI without OHCA (STEMI no OHCA). CAD severity was assessed by a single physician blinded to the resuscitation method, time to ROSC and level of consciousness. RESULTS: Between 2016 and 2022, 71 conscious OHCA, 157 comatose OHCA, 50 E-CPR OHCA and 101 STEMI no OHCA underwent immediate coronary angiography. Acute culprit lesion was documented less often in OHCA (88.1% vs 97%; p = 0.009) but complete occlusion was more frequent (68.8% vs 58.4%; p = 0.038) than in STEMI no OHCA. SYNTAX score was 5.6 in STEMI no OHCA, 10.2 in conscious OHCA, 13.4 in comatose OHCA and 26.8 in E-CPR OHCA (p < 0.001). There was a linear correlation between SYNTAX score and delay to ROSC/ECMO initiation (r2 = 0.61; p < 0.001). Post PCI culprit TIMI 3 flow was comparable between the groups (≥86%). SYNTAX score was among independent predictors of 5-year survival which was significantly decreased in comatose OHCA (56.1%) and E-CPR OHCA (36.0%) compared to conscious OHCA (83.1%) and STEMI no OHCA (88.1%). CONCLUSION: Compared to STEMI no OHCA, OHCA was associated with increased incidence of acute coronary occlusion and more complex non culprit CAD which progressively increased from conscious OHCA to E-CPR OHCA. Severity of CAD was associated with increased delays to ROSC/ECMO initiation and decreased long term survival.

Extracorporeal Life Support in Infarct-Related Cardiogenic Shock.

BACKGROUND: Extracorporeal life support (ECLS) is increasingly used in the treatment of infarct-related cardiogenic shock despite a lack of evidence regarding its effect on mortality. METHODS: In this multicenter trial, patients with acute myocardial infarction complicated by cardiogenic shock for whom early revascularization was planned were randomly assigned to receive early ECLS plus usual medical treatment (ECLS group) or usual medical treatment alone (control group). The primary outcome was death from any cause at 30 days. Safety outcomes included bleeding, stroke, and peripheral vascular complications warranting interventional or surgical therapy. RESULTS: A total of 420 patients underwent randomization, and 417 patients were included in final analyses. At 30 days, death from any cause had occurred in 100 of 209 patients (47.8%) in the ECLS group and in 102 of 208 patients (49.0%) in the control group (relative risk, 0.98; 95% confidence interval [CI], 0.80 to 1.19; P = 0.81). The median duration of mechanical ventilation was 7 days (interquartile range, 4 to 12) in the ECLS group and 5 days (interquartile range, 3 to 9) in the control group (median difference, 1 day; 95% CI, 0 to 2). The safety outcome consisting of moderate or severe bleeding occurred in 23.4% of the patients in the ECLS group and in 9.6% of those in the control group (relative risk, 2.44; 95% CI, 1.50 to 3.95); peripheral vascular complications warranting intervention occurred in 11.0% and 3.8%, respectively (relative risk, 2.86; 95% CI, 1.31 to 6.25). CONCLUSIONS: In patients with acute myocardial infarction complicated by cardiogenic shock with planned early revascularization, the risk of death from any cause at the 30-day follow-up was not lower among the patients who received ECLS therapy than among those who received medical therapy alone. (Funded by the Else Kröner Fresenius Foundation and others; ECLS-SHOCK ClinicalTrials.gov number, NCT03637205.).

Coronary disease in refractory cardiac arrest undergoing resuscitation with extracorporeal membrane oxygenation.

AIMS: Because re-establishment of spontaneous circulation (ROSC) in patients with cardiac arrest is frequently not achieved by conventional cardiopulmonary resuscitation (C-CPR), selected patients may undergo resuscitation with extracorporeal membrane oxygenation (E-CPR). We compared angiographic features and percutaneous coronary intervention (PCI) between patients undergoing E-CPR and those with ROSC after C-CPR. METHODS AND RESULTS: Forty-nine consecutive E-CPR patients undergoing immediate coronary angiography admitted between August 2013 and August 2022 were matched to 49 patients with ROSC after C-CPR. Multivessel disease (69.4% vs. 34.7%; P = 0.001), ≥ 50% unprotected left main (ULM) stenosis (18.4% vs. 4.1%; P = 0.025), and ≥1 chronic total occlusion (CTO) (28.6% vs. 10.2%; P = 0.021) were more often documented in E-CPR group. There was no significant differences in the incidence, features, and distribution of acute culprit lesion which was present in >90%. Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) (27.6 vs. 13.4; P = 0.002) and GENSINI (86.2 vs. 46.0; P = 0.001) scores were increased in E-CPR group. Optimal cut-off predicting E-CPR was 19.75 for SYNTAX (sensitivity 74%, specificity 87%) and 60.50 (sensitivity 69%, specificity 75%) for GENSINI score. More lesions were treated (1.3 vs. 1.1 lesions/patient; P = 0.002) and stents implanted (2.0 vs. 1.3/patient; P < 0.001) in E-CPR group. Final TIMI three flow was comparable (88.6% vs. 95.7%; P = 0.196) but residual SYNTAX (13.6 vs. 3.1; P < 0.001) and GENSINI (36.7 vs. 10.9; P < 0.001) scores remained increased in E-CPR group. CONCLUSION: Extracorporeal membrane oxygenation patients have more multivessel disease, ULM stenosis, and CTO but similar incidence, features, and distribution of acute culprit lesion. Despite more complex PCI, revascularization is less complete.

High fidelity ECMO simulation: a reality check with reality-use of simulation in ECMO teaching program.

Simulation based learning is becoming a crucial part in ECMO education. Simulation can provide a safe but also very realistic learning experience depending on simulation fidelity. In our institution we developed a simulation based ECMO training program that incorporates low- and high-fidelity simulation. Aim of this study was to evaluate effectiveness of low- and high-fidelity simulation teaching strategies in ECMO novices. We conducted four consecutive ECMO training courses that included fifty-one ECMO novices. We describe ECMO training execution and evaluate training effectiveness and perception by structured pre- and post-training questionnaires analysis. Results of our study show extremely high satisfaction rate with simulation training (4.9 ± 0.3, Lickert 5 point scale). High-fidelity simulation was perceived as very realistic and as such represents an important tool in learning immersion and experience. However, participants reported significant decline from their expectations with regard to structured approach to troubleshooting (4.7 ± 0.5 vs 4.3 ± 0.7, p = 0.02) and efficiency improvement (4.7 ± 0.5 vs 4.3 ± 0.6, p = 0.002) after high-fidelity simulation. There was also a significant decline from their expectation on self-confidence improvement (4.7 ± 0.5 vs 4.2 ± 0.7, p = 0.001). Our results therefore show, that complex high-fidelity simulation should probably be used with caution in novice participants, not to discourage them from further learning.

Long-Term Survival and Quality of Life in Non-Surgical Adult Patients Supported with Veno-Arterial Extracorporeal Oxygenation.

BACKGROUND: The use of veno-arterial extracorporeal membrane oxygenation (VA ECMO) for hemodynamic support is on the rise. Not much is known about the impact of extracorporeal membrane oxygenation (ECMO) and its complications on long-term survival and quality of life. METHODS: In this single-center, cross-sectional study, we evaluated the survival and quality of life in patients treated with VA ECMO between May 2009 and July 2019. Follow-up was conducted between November 2019 and January 2020. RESULTS: Overall, 118 patients were evaluated in this study. Of the 37 patients who were alive at hospital discharge, 32 answered the EuroQol-5 dimensional-5-level questionnaire (EQ-5D-5L). For patients discharged alive from the hospital, mean survival was 8.1 years, 8.4 years for cardiogenic shock, and 5.0 years for patients with refractory cardiac arrest. EQ-5D-5L index value of ECMO survivors was not significantly different from the general age-matched population. Neurologic complications and major bleeding during index hospitalization limit long-term quality of life. CONCLUSIONS: Patients treated with VA ECMO have high in-hospital mortality, with extracorporeal membrane oxygenation cardio-pulmonary resuscitation patients being at higher risk of early death. However, once discharged from the hospital, most patients remain alive with a reasonable quality of life.

Coronary artery disease burden relation with the presentation of acute cardiac events and ventricular fibrillation.

OBJECTIVES: Evaluate the differences in coronary artery disease (CAD) burden between patients with ischemic resuscitated, ischemic refractory VT/VF OHCA events and N/STEMI. BACKGROUND: Refractory out-of-hospital cardiac arrest patients presenting with initial shockable rhythms (VT/VF OHCA) have the highest mortality among patients with acute cardiac events. No predictors of VT/VF OHCA refractoriness have been identified. METHODS: A retrospective cohort design was used to assess baseline characteristics, clinical outcomes, and the angiographic severity of disease among patients with VT/VF OHCA undergoing emergent coronary angiography at the University of Minnesota Medical Center. The Gensini score was calculated for all patients to assess the angiographic burden of CAD. For patients with ischemia-related cardiac arrest, outcomes were further compared to an independent non-OHCA population presenting with N/STEMI. RESULTS: During the study period, 538 patients were admitted after VT/VF OHCA. Among them, 305 presented with resuscitated, and 233 with refractory VT/VF. 66% of resuscitated and 70% of refractory VT/VF had an underlying, angiographically documented, ischemic etiology. Ischemic resuscitated and refractory VT/VF had significant differences in Gensini score, (80.7 ± 3.6 and 127.6 ± 7.1, respectively, p < 0.001) and survival (77.3% and 30.0%, respectively, p < 0.001). Both groups had a higher CAD burden and worse survival than the non-OHCA N/STEMI population (360 patients). Ischemic refractory VT/VF was significantly more likely to present with chronic total occlusion in comparison to both N/STEMI and ischemic resuscitated VT/VF. CONCLUSION: Ischemia-related, refractory VT/VF OHCA has a higher burden of CAD and the presence of CTOs compared to resuscitated VT/VF OHCA and N/STEMI.

Patients treated with venoarterial extracorporeal membrane oxygenation have different baseline risk and outcomes dependent on indication and route of cannulation.

OBJECTIVES: To investigate the baseline risk of patients treated with Extracorporeal Cardiopulmonary Membrane Oxygenation (ECMO) in relation to cannulation strategy and indication for ECMO as well as the relation of cannulation strategy with survival and secondary hospitalization outcomes. METHODS: Severity of illness and predicted mortality risk were assessed in 317 patients. Central cannulation was used in 52 patients unable to wean off cardiopulmonary bypass after cardiac surgery. Peripheral cannulation was used in 179 patients for extracorporeal cardiopulmonary resuscitation (eCPR) and in 86 patients who received ECMO for refractory cardiogenic shock (RCS). RESULTS: Acute Physiology and Chronic Health Evaluation II (APACHE II) scores were significantly worse (P < 0.01) for peripheral ECMO eCPR (23.2) vs central ECMO (14.6) and vs peripheral ECMO for RCS (18.9). Survival After Venoarterial ECMO (SAVE) scores were significantly worse for peripheral ECMO for eCPR (-7.85) and RCS (-10.38) vs central ECMO (-3.97), and P < 0.01. Peripherally cannulated patients had significantly worse renal function. No significant difference existed for survival to discharge (peripheral ECMO for eCPR, 31%; central ECMO, 44%; peripheral ECMO for refractory cardiac shock, 39.5%; and P = 0.176), although centrally cannulated patients had significantly longer treatment durations compared with peripheral ECMO for eCPR. CONCLUSIONS: Peripherally cannulated patients with eCPR had significantly worse APACHE II and SAVE scores compared to peripherally cannulated RCS or patients with central ECMO, despite having similar mortality.

Emergency veno-arterial extracorporeal membrane oxygenation (VA ECMO)-supported percutaneous interventions in refractory cardiac arrest and profound cardiogenic shock.

AIMS: We investigated the spectrum of emergency veno-arterial extracorporeal membrane oxygenation (VA ECMO)-supported interventions including percutaneous coronary intervention (PCI), transcatheter aortic valve implantation (TAVI) and invasive electrophysiology (EP). METHODS AND RESULTS: Between June 2010 and February 2020, 52 consecutive patients underwent VA ECMO implantation for refractory cardiac arrest (E-CPR) and 78 for profound cardiogenic shock. Percutaneous interventions on VA ECMO included PCI (n = 29), TAVI (n = 4) and EP (n = 1). Surgical interventions were cardiac (n = 36) or non-cardiac (n = 5). During PCI, ECMO flow was maintained at 2.7 ±â€¯1.0 L/min. Of the 40 treated lesions, 48% were located on left anterior descending and 20% on the left main artery. An average 2.0 ±â€¯1.8 DES/patient with diameter 3.2 ±â€¯0.5 mm and stented length 41 ±â€¯35 mm were implanted. PCI success was 83%. TAVI was performed in 4 patients with left ventricular ejection fraction 21 ±â€¯10% and mean aortic valve gradient 41 ±â€¯5 mmHg. After successful valve implantation supported by 1.4 ±â€¯0.1 L/min ECMO flow, mean gradient decreased to 11 ±â€¯5 mmHg without significant aortic regurgitation. In one patient radiofrequency ablation of His bundle followed by permanent pacemaker implantation was performed under ECMO flow of 2.8 L/min. Overall survival to hospital discharge with good neurological recovery was 29% in E-CPR and 44% in profound cardiogenic shock. CONCLUSIONS: Our study showed feasibility and effectiveness of VA ECMO-supported percutaneous interventions in patients with profound hemodynamic collapse.

Increased QT Dispersion Is Linked to Worse Outcomes in Patients Hospitalized for Out-of-Hospital Cardiac Arrest.

Background The incidence and mortality of out-of-hospital cardiac arrest (OHCA) remains high, but predicting outcomes is challenging. Being able to better assess prognosis of hospitalized patients after return of spontaneous circulation would enable improved management of survival expectations. In this study, we assessed the predictive value of ECG indexes in hospitalized patients with OHCA. Methods and Results PR interval and QT interval corrected by the Bazett formula (QTc) for all leads were calculated from standard 12-lead ECGs 24 hours after return of spontaneous circulation in 93 patients who were hospitalized following OHCA. PR interval and QT and QTc duration did not differentiate OHCA survivors and nonsurvivors. However, QT and QTc dispersion was significantly increased in patients who died during hospitalization compared with survivors discharged from the hospital (P<0.01). Logistic regression indicated a strong association between increased QT dispersion and in-hospital mortality (P<0.0001; area under the curve, 0.8918 for QT dispersion and 0.8673 for QTc dispersion). Multinomial logistic regression indicated that the increase of QTc dispersion correlated with worse Cerebral Performance Category scores at discharge (P<0.001; likelihood ratio, 51.42). There was also significant correlation between dispersion measures and serum potassium at the time of measurement and between dispersion measures and cumulative epinephrine administration. No difference existed regarding the number of measurable leads. Conclusions Lesser QT and QTc dispersion at 24 hours after return of spontaneous circulation was significantly associated with survival and neurologic status at discharge. Routine evaluation of QT and QTc dispersion during hospitalization following return of spontaneous circulation might improve outcome prognostication for patients hospitalized for OHCA.

Extracorporeal cardiopulmonary resuscitation for cardiac arrest.

PURPOSE OF REVIEW: Extracorporeal cardiopulmonary resuscitation (ECPR) is a contemporary resuscitation approach that employs veno-arterial extracorporeal membrane oxygenation (VA-ECMO). This approach is increasingly used worldwide to mitigate the widespread hemodynamic and multiorgan dysfunction that accompanies cardiac arrest. RECENT FINDINGS: In this review, the physiology of VA-ECMO and ECPR, the role of ECPR in contemporary resuscitation care, the complications associated with ECPR and VA-ECMO usage, and intensive care considerations for this population are discussed. SUMMARY: ECPR offers a promising mechanism to mitigate multiorgan injury and allow time for the institution of supportive interventions required to effectively treat cardiac arrest. More prospective data in the context of extensive prehospital and hospital collaboration is needed to promote its successful use.

Cardiopulmonary Resuscitation with Extracorporeal Membrane Oxygenation in a Patient with Profound Accidental Hypothermia and Refractory Ventricular Fibrillation.

We describe a patient with severe accidental hypothermia (≤25.4°C) and prolonged refractory ventricular fibrillation, lasting at least 4 hours and 8 minutes, who underwent cardiopulmonary resuscitation with extracorporeal membrane oxygenation and survived without neurologic deficit.

One-Year Outcomes after PCI Strategies in Cardiogenic Shock.

BACKGROUND: Among patients with acute myocardial infarction, cardiogenic shock, and multivessel coronary artery disease, the risk of a composite of death from any cause or severe renal failure leading to renal-replacement therapy at 30 days was found to be lower with percutaneous coronary intervention (PCI) of the culprit lesion only than with immediate multivessel PCI. We evaluated clinical outcomes at 1 year. METHODS: We randomly assigned 706 patients to either culprit-lesion-only PCI or immediate multivessel PCI. The results for the primary end point of death or renal-replacement therapy at 30 days have been reported previously. Prespecified secondary end points at 1 year included death from any cause, recurrent myocardial infarction, repeat revascularization, rehospitalization for congestive heart failure, the composite of death or recurrent infarction, and the composite of death, recurrent infarction, or rehospitalization for heart failure. RESULTS: As reported previously, at 30 days, the primary end point had occurred in 45.9% of the patients in the culprit-lesion-only PCI group and in 55.4% in the multivessel PCI group (P=0.01). At 1 year, death had occurred in 172 of 344 patients (50.0%) in the culprit-lesion-only PCI group and in 194 of 341 patients (56.9%) in the multivessel PCI group (relative risk, 0.88; 95% confidence interval [CI], 0.76 to 1.01). The rate of recurrent infarction was 1.7% with culprit-lesion-only PCI and 2.1% with multivessel PCI (relative risk, 0.85; 95% CI, 0.29 to 2.50), and the rate of a composite of death or recurrent infarction was 50.9% and 58.4%, respectively (relative risk, 0.87; 95% CI, 0.76 to 1.00). Repeat revascularization occurred more frequently with culprit-lesion-only PCI than with multivessel PCI (in 32.3% of the patients vs. 9.4%; relative risk, 3.44; 95% CI, 2.39 to 4.95), as did rehospitalization for heart failure (5.2% vs. 1.2%; relative risk, 4.46; 95% CI, 1.53 to 13.04). CONCLUSIONS: Among patients with acute myocardial infarction and cardiogenic shock, the risk of death or renal-replacement therapy at 30 days was lower with culprit-lesion-only PCI than with immediate multivessel PCI, and mortality did not differ significantly between the two groups at 1 year of follow-up. (Funded by the European Union Seventh Framework Program and others; CULPRIT-SHOCK ClinicalTrials.gov number, NCT01927549 .).

PCI Strategies in Patients with Acute Myocardial Infarction and Cardiogenic Shock.

BACKGROUND: In patients who have acute myocardial infarction with cardiogenic shock, early revascularization of the culprit artery by means of percutaneous coronary intervention (PCI) improves outcomes. However, the majority of patients with cardiogenic shock have multivessel disease, and whether PCI should be performed immediately for stenoses in nonculprit arteries is controversial. METHODS: In this multicenter trial, we randomly assigned 706 patients who had multivessel disease, acute myocardial infarction, and cardiogenic shock to one of two initial revascularization strategies: either PCI of the culprit lesion only, with the option of staged revascularization of nonculprit lesions, or immediate multivessel PCI. The primary end point was a composite of death or severe renal failure leading to renal-replacement therapy within 30 days after randomization. Safety end points included bleeding and stroke. RESULTS: At 30 days, the composite primary end point of death or renal-replacement therapy had occurred in 158 of the 344 patients (45.9%) in the culprit-lesion-only PCI group and in 189 of the 341 patients (55.4%) in the multivessel PCI group (relative risk, 0.83; 95% confidence interval [CI], 0.71 to 0.96; P=0.01). The relative risk of death in the culprit-lesion-only PCI group as compared with the multivessel PCI group was 0.84 (95% CI, 0.72 to 0.98; P=0.03), and the relative risk of renal-replacement therapy was 0.71 (95% CI, 0.49 to 1.03; P=0.07). The time to hemodynamic stabilization, the risk of catecholamine therapy and the duration of such therapy, the levels of troponin T and creatine kinase, and the rates of bleeding and stroke did not differ significantly between the two groups. CONCLUSIONS: Among patients who had multivessel coronary artery disease and acute myocardial infarction with cardiogenic shock, the 30-day risk of a composite of death or severe renal failure leading to renal-replacement therapy was lower among those who initially underwent PCI of the culprit lesion only than among those who underwent immediate multivessel PCI. (Funded by the European Union 7th Framework Program and others; CULPRIT-SHOCK ClinicalTrials.gov number, NCT01927549 .).

Emergency percutaneous implantation of veno-arterial extracorporeal membrane oxygenation in the catheterisation laboratory.

AIMS: Our aim was to describe our protocol for emergency percutaneous implantation of femoral veno-arterial extracorporeal membrane oxygenation (VA ECMO) in the catheterisation laboratory and to compare its effectiveness and safety with implantation in the intensive care unit and the operating room. METHODS AND RESULTS: Our retrospective observational study enrolled 56 consecutive patients undergoing VA ECMO implantation in the catheterisation laboratory (n=23), the intensive care unit (n=8) and the operating room (n=25). Among patients undergoing catheterisation laboratory implantation, 11 patients had profound cardiogenic shock but preserved arterial pulsations, and 12 patients had refractory cardiac arrest undergoing automated mechanical chest compression. Using our fluoroscopy-guided protocol, arterial and venous cannulas were successfully implanted and the desired ECMO flow obtained in each patient. There was no vessel perforation/dissection. Moderate/severe GUSTO or BARC 3 and 5 bleeding occurred in 13%. Ipsilateral limb ischaemia occurred in one of eight patients (13%) with upfront perfusion sheath implantation, and in two of three patients (75%) in whom this strategy was not used (p=0.15). There was no infection at the site of cannula implantation. Complications related to implantation in the catheterisation laboratory were comparable to surgical implantation in the operating room and percutaneous implantation in the intensive care unit using ultrasound guidance. CONCLUSIONS: Fluoroscopy-guided emergency implantation of femoral VA ECMO by an interventional cardiologist in the catheterisation laboratory is effective and safe for both patients in cardiogenic shock and those in refractory cardiac arrest.

Fulminant high altitude blindness.

Prolonged altitude exposure even with acclimatization continues to present a physiological challenge to all organ systems including the central nervous system. We describe a case of a 41-year-old Caucasian female climber who suffered severe visual loss that was due to possible optic nerve pathology occurring during a high altitude expedition in the Himalayas. This case is atypical of classic high altitude cerebral oedema and highlights yet another danger of prolonged sojourn at extreme altitudes.

Contrast layering artefact mimicking aortic dissection in a patient on veno-arterial extracorporeal membrane oxygenation undergoing computed tomography scan.

Interpretation and evaluation of images obtained by different contrast-enhanced diagnostic tools in patients on extracorporeal membrane oxygenation (ECMO) support can be extremely challenging due to profound pump-related alterations in haemodynamics and contrast media enhancement patterns. We present a case of a 65-year old patient on veno-arterial ECMO with a pseudo-filling defect of the arterial system on contrast-enhanced computed tomography scan, resembling aortic dissection.