Acute coronary thrombotic occlusion is the most common trigger of cardiac arrest. The aim of the present study was to assess the impact of an invasive strategy characterized by emergency coronary angiography and subsequent percutaneous coronary intervention (PCI), if indicated, on in-hospital survival of resuscitated patients with out-of-hospital cardiac arrest (OHCA) and no obvious extracardiac cause who do not regain consciousness soon after recovery of spontaneous circulation. Ninety-three consecutive patients (67 ± 12 years old, 76% men) were included in the study. Clinical characteristics and coronary angiographic and in-hospital outcome data were retrospectively collected. Multivariate Cox proportional-hazards analysis was performed to identify independent determinants of in-hospital survival. Coronary angiography was performed in 66 patients (71%). Forty-eight patients underwent emergency coronary angiography; in the remaining 18 patients, mean time from OHCA to coronary angiography was 13 ± 10 days. In patients referred to emergency coronary angiography, successful emergency PCI of a culprit coronary lesion was performed in 25 patients (52%). In-hospital survival rate was 54%. At multivariate analysis, emergency coronary angiography (hazard ratio 2.32, 95% confidence interval 1.23 to 4.38, p = 0.009) and successful emergency PCI (hazard ratio 2.54, 95% confidence interval 1.35 to 4.8, p = 0.004) were independently related to in-hospital survival in the overall study population; delay in performing coronary angiography (hazard ratio 0.95, 95% confidence interval 0.92 to 0.99, p = 0.013) was independently related to in-hospital mortality in patients referred to coronary angiography. In conclusion, an invasive strategy characterized by emergency coronary angiography and subsequent PCI, if indicated, seems to improve in-hospital outcome of resuscitated but unconscious patients with OHCA without obvious extracardiac cause.
Acute coronary thrombotic occlusion is the most common trigger of cardiac arrest. Few recent retrospective studies and prospective registries have suggested a beneficial effect of emergency coronary angiography and percutaneous coronary intervention (PCI) on the outcome of resuscitated patients with out-of-hospital cardiac arrest (OHCA). The benefit seems to be well established in patients who regain consciousness soon after recovery of spontaneous circulation (ROSC). Conversely, whether emergency coronary angiography and PCI improve survival in patients who remain unconscious after ROSC remains unknown. Therefore, the aim of the present study was to assess the impact of an invasive strategy characterized by emergency coronary angiography and subsequent PCI, if indicated, on in-hospital survival of resuscitated unconscious patients with OHCA without obvious extracardiac cause.
Methods
The Province of Udine including urban, suburban, and rural areas has approximately 550,000 inhabitants and is served by a centrally coordinated ambulance system (118 Operative Station). For established OHCA, resuscitation is delivered by an emergency team. Patients in whom ROSC is achieved are then referred to our institution, which is a tertiary center with intensive care units, a coronary care unit, and a coronary intervention facility available 24 hours a day, 7 days a week. In this retrospective analysis, the clinical characteristics and outcome of consecutive unconscious patients resuscitated from OHCA without obvious extracardiac cause and admitted to the intensive care unit of our institution from 2008 through 2011 were evaluated.
Patients were included in the study if they fulfilled the following inclusion criteria: (1) age >18 years; (2) sustained ROSC, defined as >20 minutes; (3) persistent unconscious state at hospital admission; and (4) absence of any obvious extracardiac cause (such as respiratory failure, brain injury, metabolic disorder, hemorrhage, drug overdose). For each patient fulfilling the inclusion criteria, medical records were reviewed to document the presence of coronary risk factors and history of coronary artery disease (CAD). A history of CAD was defined as previous acute coronary syndrome, percutaneous or surgical coronary revascularization, and/or ≥1 angiographically documented coronary stenosis with ≥50% luminal diameter.
Data related to the early phase of OHCA were collected according to Utstein recommendations and included symptoms preceding collapse (i.e., chest pain, dyspnea, of syncope), witnessed cardiac arrest, bystander resuscitation, initial arrest rhythm (i.e., ventricular fibrillation/ventricular tachycardia, or pulseless electrical activity/asystole), time from collapse to ROSC >20 minutes, and post-ROSC electrocardiographic (ECG) pattern (i.e., ST-segment elevation or other ECG patterns).
Coronary angiographic data were also collected. Of note, during the study period the decision to perform emergency or delayed coronary angiography was taken by the treating cardiologist based on clinical judgment and according to existing guidelines. Coronary lesions resulting in ≥50% decrease in luminal diameter were considered significant. Thrombotic occlusion and irregular eccentric stenoses with a narrow neck, acute angles or craters, and thrombotic apposition were judged to represent acute or recent culprit coronary lesions ; in these cases, PCI was subsequently performed. PCI was deemed successful if it resulted in residual stenosis of <50% with Thrombolysis In Myocardial Infarction grade 3 flow.
The outcome of the study was survival at time of hospital discharge. Neurologic status at that time was also assessed using the Cerebral Performance Categories scale ; a Cerebral Performance Categories score ≤2 indicates recovery without major neurologic impairment.
Continues variables are expressed as mean ± SD when normally distributed and as median and interquartile range when non-normally distributed. Categorical data are presented as absolute number and percentage. Differences in continuous variables were assessed using Student’s t test or Mann–Whitney U test as appropriate. Chi-square test or Fisher exact test, if appropriate, was computed to assess differences in categorical variables. Mantel–Haenszel test for time-to-event data with respect to the primary outcome was used for statistical comparison between patients referred to emergency coronary angiography and the remaining study population. Multivariate Cox proportional-hazards analysis was performed to identify the independent determinants of outcome in the overall study population and in patients referred to coronary angiography. Variables with a p value <0.2 at univariate analysis were entered as covariates in the multivariate analysis using the stepwise backward likelihood ratio selection method. For each variable, the hazard ratio and 95% confidence interval were calculated.
All statistical analyses were performed using SPSS 20 for Windows (SPSS, Inc., Chicago, Illinois). A 2-tailed p value <0.05 was considered statistically significant.
Results
Ninety-three patients fulfilled the inclusion criteria and were entered in the study. Demographic and clinical characteristics of the study population are presented in Table 1 . Table 2 presents differences between patients with and without known CAD. Mean age was 67 ± 12 years; 71 (76%) patients were men. Coronary angiography during hospitalization was performed in 66 patients (71%). Forty-eight patients underwent emergency coronary angiography; in the remaining 18 patients, mean time from OHCA to coronary angiography was 13 ± 10 days. In patients referred to coronary angiography, significant CAD was observed in 57 patients (86%). No significant difference in prevalence of significant CAD was present between patients with ventricular fibrillation/ventricular tachycardia and those with pulseless electrical activity/asystole as initial arrest rhythm (n = 43, 84%, vs n = 14, 93%, p = 0.45); a trend toward a higher prevalence of significant CAD was observed in patients with ST-segment elevation compared to those with other ECG patterns on post-ROSC electrocardiogram (n = 27, 96%, vs n = 30, 79%, p = 0.067).
| Variable | All Patients (n = 93) | Emergency Coronary Angiography (n = 48) | Delayed or No Coronary Angiography (n = 45) | p Value |
|---|---|---|---|---|
| Age (years) | 0.063 | |||
| ≤60 | 27 (29%) | 18 (38%) | 9 (20%) | |
| >60 | 66 (71%) | 30 (62%) | 36 (80%) | |
| Men | 71 (76%) | 38 (79%) | 33 (73%) | 0.51 |
| Smoker | 48 (52%) | 25 (52%) | 23 (51%) | 0.34 |
| Hypertension | 59 (63%) | 30 (63%) | 29 (64%) | 0.85 |
| Diabetes mellitus | 19 (20%) | 8 (17%) | 11 (24%) | 0.35 |
| Dyslipidemia ⁎ | 21 (23%) | 12 (25%) | 9 (20%) | 0.56 |
| Known coronary artery disease | 30 (32%) | 17 (35%) | 13 (29%) | 0.50 |
| Preceding symptoms | 25 (27%) | 15 (31%) | 10 (22%) | 0.33 |
| Witnessed arrest | 78 (84%) | 40 (83%) | 38 (84%) | 0.88 |
| Bystander cardiopulmonary resuscitation | 53 (57%) | 24 (50%) | 29 (64%) | 0.16 |
| Initial rhythm | 0.029 | |||
| Pulseless electrical activity or asystole | 33 (35%) | 12 (25%) | 21 (47%) | |
| Ventricular tachycardia or ventricular fibrillation | 60 (65%) | 36 (75%) | 24 (53%) | |
| Time from collapse to recovery of spontaneous circulation | 0.60 | |||
| ≤20 minutes | 47 (51%) | 23 (48%) | 24 (53%) | |
| >20 minutes | 46 (49%) | 25 (52%) | 21 (47%) | |
| Electrocardiogram after recovery of spontaneous circulation | <0.001 | |||
| ST-segment elevation | 32 (34%) | 28 (58%) | 4 (9%) | |
| Other electrocardiographic pattern † | 61 (66%) | 20 (42%) | 41 (91%) |
⁎ Defined as total cholesterol level ≥240 mg/dl and/or triglyceride level >150 mg/dl.
† In patients with another electrocardiographic pattern, 7 had left bundle branch block (3 patients referred to emergency coronary angiography and 4 patients with delayed or no coronary angiography).
| Variable | Patients With Known CAD (n = 30) | Patients Without Known CAD (n = 63) | p Value |
|---|---|---|---|
| Age (years) | 0.40 | ||
| ≤60 | 7 (23%) | 20 (32%) | |
| >60 | 23 (77%) | 43 (68%) | |
| Men | 24 (80%) | 47 (75%) | 0.57 |
| Smoker | 12 (40%) | 36 (57%) | 0.12 |
| Hypertension | 19 (63%) | 40 (64%) | 0.99 |
| Diabetes mellitus | 7 (23%) | 12 (19%) | 0.63 |
| Dyslipidemia ⁎ | 12 (40%) | 9 (14%) | 0.006 |
| Preceding symptoms | 12 (40%) | 13 (21%) | 0.049 |
| Witnessed arrest | 26 (87%) | 52 (83%) | 0.77 |
| Bystander cardiopulmonary resuscitation | 19 (63%) | 34 (54%) | 0.39 |
| Initial rhythm | 0.87 | ||
| Pulseless electrical activity or asystole | 11 (37%) | 22 (35%) | |
| Ventricular tachycardia or ventricular fibrillation | 19 (63%) | 41 (65%) | |
| Time from collapse to recovery of spontaneous circulation | 0.94 | ||
| ≤20 minutes | 15 (50%) | 32 (51%) | |
| >20 minutes | 15 (50%) | 31 (49%) | |
| Electrocardiogram after recovery of spontaneous circulation | 0.75 | ||
| ST-segment elevation | 11 (37%) | 21 (33%) | |
| Other electrocardiographic pattern | 19 (63%) | 42 (67%) | |
| Coronary angiography | 0.50 | ||
| Emergency | 17 (57%) | 31 (49%) | |
| Delayed or not performed | 13 (43%) | 32 (51%) |
⁎ Defined as total cholesterol level ≥240 mg/dl and/or triglyceride level >150 mg/dl.
An acute or recent culprit coronary lesion was observed in 38 patients (58%). No significant difference in the prevalence of culprit coronary lesion was present between patients with ventricular fibrillation/ventricular tachycardia and those with pulseless electrical activity/asystole as initial arrest rhythm (n = 31, 61%, vs n = 7, 47%, p = 0.38); conversely, culprit coronary lesions were more frequently observed in patients with ST-segment elevation compared to those with other ECG patterns on post-ROSC electrocardiogram (n = 22, 79%, vs n = 16, 42%, p = 0.005).
In patients referred to emergency coronary angiography, successful emergency PCI of a culprit coronary lesion was performed in 25 patients (52%); in patients referred to delayed coronary angiography, successful PCI of a presumed culprit coronary lesion was performed in 6 patients (33%).
In-hospital survival was 54% (n = 50 patients); of these, 36 patients (72%) reached a Cerebral Performance Categories level of 1 or 2, indicating a favorable neurologic outcome. Median time from OHCA to hospital discharge for survivor patients was 19 days (interquartile range 12 to 44). In patients referred to emergency coronary angiography, 29 patients (60%) were discharged alive after a median time from OHCA of 18 days (interquartile range 11 to 28). Twenty-one patients (47%) with delayed or no coronary angiography were discharged alive after a median time from OHCA of 38 days (interquartile range 15 to 64, p = 0.018, compared to patients referred to emergency coronary angiography).
Table 3 and Figure 1 present results of univariate and multivariate analyses performed to determine independent correlates of survival at time of hospital discharge. In the overall study population (n = 93), age >60 years, emergency coronary angiography, and successful emergency PCI were independently related to outcome ( Figure 1 ). In patients referred to coronary angiography (n = 66), age >60 years and delay in coronary angiography were found as independent determinants of outcome ( Figure 1 ).
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