ASAIO Journal 2014
Management of Cardiac Arrest Caused by Acute Massive Pulmonary Thromboembolism: Importance of Percutaneous Cardiopulmonary Support Yang Hyun Cho,* Wook Sung Kim,* Kiick Sung,* Dong Seop Jeong,* Young Tak Lee,* Pyo Won Park,* and Duk-Kyung Kim†
Cardiac arrest caused by acute pulmonary embolism is associated with high patient mortality. We reviewed patients who had cardiac arrest caused by acute pulmonary embolism. Between January 2001 and September 2013, we identified 20 patients at our institution with a confirmative diagnosis of acute pulmonary thromboembolism and cardiac arrest. Percutaneous cardiopulmonary support (PCPS) and surgical embolectomy are the standard course of care for patients with shock or cardiac arrest caused by pulmonary thromboembolism at our institution. Patients were divided into two groups (PCPS group and non-PCPS group). Percutaneous cardiopulmonary support was used in 60% of patients. Surgical embolectomy was performed for 85% of patients. Overall in-hospital and surgical mortalities were 35% and 29%, respectively. On the basis of the multivariate analysis, both cardiopulmonary resuscitation more than 15 minutes and absence of PCPS were significant risk factors affecting survival (p = 0.001 and 0.049, respectively). When the duration of cardiac arrest is short, surgical embolectomy is a viable option after cardiac arrest caused by pulmonary thromboembolism. Percutaneous cardiopulmonary support may be a useful tool for both stabilizing the patient and providing a bridge when deciding on further management options. ASAIO Journal 2014; 60:280–283.
most effective method to treat PTE, it is usually performed when other modalities have failed or are contraindicated.1,2 One of the primary reasons contributing to the lower prevalence of surgical embolectomy is a surgical mortality rate as high as 20–30%.3,4 Indeed, reviews of data on surgical mortality after embolectomy include a number of high-risk situations including cardiac arrest and cardiopulmonary collapse, and the mortality of surgical embolectomy in such circumstances is reported as more than 50%.4–6 Percutaneous cardiopulmonary support (PCPS), which involves the use of extracorporeal membrane oxygenation (ECMO), has been suggested as a bridge-to-surgical embolectomy by some authors.7–9 Percutaneous cardiopulmonary support is also used as a part of cardiopulmonary resuscitation (CPR) in some centers, including our hospital.10–12 We have previously reported our use of extracorporeal CPR to assist conventional CPR,13,14 and emergent surgical embolectomy with or without PCPS is our preferred method to treat patients with acute massive PTE. In this retrospective study, we hypothesized that the use of PCPS is an important predictor of prognosis and surgical outcome for these patients.
Key Words: pulmonary embolism, extracorporeal membrane oxygenation, cardiac arrest, surgical embolectomy, cardiopulmonary resuscitation
Between January 2001 and September 2013, we identified 176 patients with acute massive or submassive PTE at Samsung Medical Center. A total of 20 patients (11%) who experienced cardiac arrest at initial presentation or after diagnosis of PTE were included in this study. Percutaneous cardiopulmonary support was performed in 12 patients (60%, PCPS group) to assist CPR or stabilize patients after recovery of spontaneous circulation (ROSC). Exclusion criteria were nonsurvivors of CPR, out-of-hospital cardiac arrest, and no evidence of PTE in imaging studies such as computed tomography, fluoroscopic angiography, and echocardiography. We divided patients into two groups, PCPS group and non-PCPS group (n = 8, 40%). Medical records for patients in each group were reviewed. The Samsung Medical Center Institutional Review Board approved this study and waived the need for patient consent.
Methods Study Subjects
Treatment modalities for acute massive pulmonary thromboembolism (PTE) consist of systemic anticoagulation, thrombolysis, catheter-based fragmentation and embolectomy, and surgical embolectomy. Although surgical embolectomy is the
From the *Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea; and †Department of Internal Medicine, Division of Cardiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. Submitted for consideration November 25, 2013; accepted for publication in revised form February 18, 2014. Disclosures: The authors have no conflicts of interest to report. Reprint Requests: Wook Sung Kim, MD, Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Korea. Email: [email protected]. Copyright © 2014 by the American Society for Artificial Internal Organs
CPR and PCPS The rapid response team of our institution calls the ECMO team when CPR is performed for more than 10 minutes or when a patient’s vital signs are unstable after ROSC. The leader of the ECMO team is a cardiovascular surgeon or interventional cardiologist. Percutaneous cardiopulmonary support
DOI: 10.1097/MAT.0000000000000063
280
281
CARDIAC ARREST BY PULMONARY THROMBOEMBOLISM
was established to terminate conventional CPR or maintain stable hemodynamics. We did not perform PCPS if the patient is stable after ROSC without recurrent cardiac arrest. The Capiox Emergency Bypass System (Terumo, Tokyo, Japan) or Prolonged Life Support System (Maquet Cardiopulmonary AG, Hirrlingen, Germany) was used in all cases. Two cannulae through the femoral artery and vein were inserted by Seldinger’s technique. A catheter was inserted into the superficial femoral artery to facilitate distal limb perfusion if needed. Anticoagulation was accomplished by a bolus injection of unfractionated heparin, followed by a continuous intravenous infusion of heparin to maintain an activated clotting time between 150 and 200 seconds. The flow rate was set to maintain a mean arterial pressure greater than 60 mm Hg. Cardiac arrest occurred in the operating room for seven patients. In these cases, the chest was opened directly and a standard cardiopulmonary bypass was performed while chest compressions and manual cardiac massage were performed. Surgical Pulmonary Artery Embolectomy At our institution, surgical embolectomy is the preferred method for management of acute massive PTE when the patient is in refractory shock or cardiac arrest. Surgery was performed whenever there was some chance of survival. Standard median sternotomy and cardiopulmonary bypass were performed. We removed all emboli up to the segmental pulmonary arteries. A brief period of circulatory arrest was encountered in five patients (median time of 4 minutes, range 1–35). Patients were able to be weaned off PCPS intraoperatively in all cases. Concomitant procedures were intracardiac thrombi removal (n = 2) and tricuspid annuloplasty (n = 1). Statistical Analysis Continuous variables were expressed as the mean ± standard deviation or median with interquartile range where appropriate. Continuous and categorical variables were compared using the Mann–Whitney U test or Fisher’s exact test, respectively. A multivariate cox regression model with model selection using forward stepwise method was used to identify risk factors for survival. Variables used for model selection were female, age, hypertension, diabetes mellitus, malignancy, CPR duration of more than 15 minutes, PCPS, thrombolysis, and surgical thrombectomy. A Kaplan–Meier curve was generated to show the trend
of midterm survival, and a log-rank test was used to compare survival curves between the groups. SPSS version 21.0 (SPSS Inc., Chicago, IL) was used for statistical analysis. A two-tailed p value of less than 0.05 was considered statistically significant. Results Patient Characteristics and Resuscitation The diagnosis of pulmonary embolism was made by computed tomography (n = 16, 84%), fluoroscopic angiography (n = 2, 11%), and transesophageal echocardiography (n = 1, 5%). All patients experienced cardiac arrest in the hospital. Cardiac arrest occurred in the operating room while preparing for surgical embolectomy in seven patients. Percutaneous cardiopulmonary support was used as a part of CPR or to stabilize the patient after ROSC in 12 patients (60%). Reasons for terminating CPR were ROSC (n = 13, 68%), initiation of PCPS (n = 4, 21%), or commencement of cardiopulmonary bypass in the operating room (n = 2, 11%). The most common predisposing cause of PTE was immobilization (58%). Three patients had thrombolysis for treatment of PTE and subsequently experienced cardiac arrest. There were no statistically significant parameters for patient survival except duration of CPR. Details of patient profiles are shown in Table 1. Surgical Embolectomy and Clinical Outcomes Surgical embolectomy was performed in 16 patients (84%). All patients with CPR duration of 15 minutes or less had surgery, whereas six of nine patients (67%) with CPR duration of more than 15 minutes underwent surgery. In three patients, surgical embolectomy was withheld, because it was thought to be futile. There were five in-hospital mortalities (31%) after surgical embolectomy. The in-hospital mortality after surgery was 0% in CPR duration of 15 minutes or less and 78% in CPR duration of more than 15 minutes. Causes of death were inability to be weaned from cardiopulmonary bypass (n = 2, 40%), anoxic brain damage (n = 2, 40%), and multiple organ failure (n = 1, 20%). Two patients had mediastinal re-exploration for postoperative bleeding (13%). History of hypertension, CPR lasting more than 15 minutes, and no use of PCPS were risk factors affecting the overall survival according to the multivariate analysis (Table 2 and Figure 1).
Table 1. Patient Characteristics Variables Female (%) Mean age, years (SD) Hypertension Diabetes mellitus Pregnancy related Immobilization Malignancy Duration of CPR, minutes (SD) Thrombolysis Surgical embolectomy CPB time (min)
Total
PCPS Group n = 12
Non-PCPS Group n=8
p
12 (60%) 57.81 (18.303) 9 (45%) 9 (45%) 3 (15%) 12 (60%) 4 (20%) 19.32 (17.531) 3 (15%) 17 (85%) 126.4 (65.202)
6 (50%) 60 (20.14) 6 (50%) 6 (50%) 1 (8%) 8 (67%) 3 (25%) 20.25 (17.884) 2 (17%) 9 (75%) 105 (24.885)
6 (75%) 54.53 (15.853) 3 (38%) 3 (38%) 2 (25%) 4 (50%) 1 (13%) 16.13(17.431) 1 (13%) 8 (100%) 153.86 (90.753)
0.373 0.418 0.67 0.67 0.537 0.648 0.619 0.462 1.000 0.242 0.873
CPB, cardiopulmonary bypass; CPR, cardiopulmonary resuscitation; SD, standard deviation; PCPS, percutaneous cardiopulmonary support.
282 CHO et al. Table 2. Multivariate Analysis of Risk Factors for Survival Variables Hypertension CPR duration >15 minutes PCPS
p
Hazard Ratio (95% CI)
0.029 0.001
7.701 (1.231–48.184) 54.743 (5.175–579.114)
0.049
0.226 (0.051–0.992)
CI, confidence interval; CPR, cardiopulmonary resuscitation; PCPS, percutaneous cardiopulmonary support.
There were 13 survival to-discharges, and the overall in-hospital mortality was 35%. All patients with CPR duration of 15 minutes or less were discharged without significant disability. Two patients with CPR duration of more than 15 minutes had significant neurologic damage. A 51-year-old man underwent CPR for 23 minutes, and after stabilization with PCPS, we performed surgical embolectomy. During the early postoperative stage, he exhibited severe neurologic dysfunction; however, he recovered significantly and displayed only mild cognitive dysfunction. A 40-year-old man whose CPR time was 24 minutes had PCPS during extracorporeal CPR. While preparing for emergent surgery, he had myoclonic status epilepticus, and thus the surgery was not performed and he was able to be weaned off PCPS after 2 days. At the time of the last follow-up, the patient remained in a vegetative state. Discussion In instances of cardiac arrest, surgical embolectomy is usually considered as a first-line treatment because it promptly resolves obstruction. Thus, this surgery is often performed in devastating situations. Despite a lack of clear evidence, current guidelines recommend surgical embolectomy if thrombolysis is contraindicated or fails.1,2 The high surgical mortality of embolectomy is considered an inevitable result of perioperative conditions such as cardiac arrest.4 In this study, we did not observe any mortality in patients whose CPR duration was 15 minutes or less. On the contrary, the in-hospital mortality of surgical embolectomy was high (78%) in patients who
underwent CPR for more than 15 minutes. Although the mortality rate of the prolonged CPR group was similar to previously reported rates, we observed a favorable outcome in patients who had a shorter duration of CPR.15,16 Thus, we believe that surgical embolectomy is still a valid option in patients who have had a short period of cardiac arrest. Duration of CPR is recognized as a universally important predictor of morbidity and mortality; however, it may be more prominent in PTE.5,15 Indeed, because the reasons for cardiac arrest in PTE include mechanical obstruction of pulmonary circulation, conventional CPR may not be as effective as in other situations. Our results suggest that prevention of cardiac arrest and reduction of CPR duration may be important for improving the outcome of PTE. Niwa et al.6 found that 11% of acute massive or submassive PTE patients experience cardiac arrest or cardiopulmonary collapse, and that the 30-day mortality of these patients is 59%. Therefore, early surgery and liberal use of PCPS may be useful for preventing catastrophic events and improving clinical outcomes. Several centers including our own hospital have recently begun to use PCPS as a part of CPR.10,11,13 Because PCPS is a partial cardiopulmonary bypass, it is effective for stabilizing patients and protects the right ventricle from the occluded pulmonary artery. Percutaneous cardiopulmonary support also can provide sufficient amounts of oxygen to the body. We have an in-house PCPS team that covers cardiac arrest without ROSC for 10 minutes. Use of PCPS improved survival in our study population. Despite prolonged CPR, there were two survivors who had PCPS-assisted resuscitation. Specifically, one patient whose duration of CPR was 23 minutes had PCPS and underwent emergent surgical embolectomy and was successfully discharged with only mild cognitive dysfunction. Conversely, another survivor had CPR for 24 minutes after which PCPS was inserted. The patient did not undergo surgery because of status epilepticus and experienced permanent severe anoxic brain damage. It is rarely necessary to perform emergent surgical embolectomy when PCPS is used, as it allows for additional time to make a decision regarding the course of action for a patient. Therefore, the role of PCPS in cardiac arrest caused
Figure 1. Kaplan–Meier survival curves for cardiac arrest after pulmonary thromboembolism according to (A) the duration of cardiopulmonary resuscitation (CPR) and (B) use of percutaneous cardiopulmonary support (PCPS). Although PCPS did not showed survival benefit in this univariate analysis, the most effective way to reduce duration of CPR is PCPS.
CARDIAC ARREST BY PULMONARY THROMBOEMBOLISM
by PTE is not only to stabilize the patient but also to provide a bridge when deciding further treatment options. Our study comprised a small number of patients and was retrospective in nature and thus may have been influenced by these limitations. Because cardiac arrest by proven acute PTE is rare, a multicenter study may be necessary. Our study does not directly suggest the usage of either surgical embolectomy or PCPS. Furthermore, although our results indicated a clear effect of CPR duration on survival, a larger scaled and randomized trial is necessary to verify these results. In conclusion, surgical embolectomy was found to be effective in patients where CPR was performed for a short duration due to acute PTE. Surgery was associated with a higher rate of mortality when CPR was performed for more than 15 minutes. Last, PCPS may be a useful tool for both patient stabilization and providing a bridge when deciding on further management options. References 1. Jaff MR, McMurtry MS, Archer SL, et al; American Heart Association Council on Cardiopulmonary, Critical Care, Perioperative and Resuscitation; American Heart Association Council on Peripheral Vascular Disease; American Heart Association Council on Arteriosclerosis, Thrombosis and Vascular Biology: Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: A scientific statement from the American Heart Association. Circulation 123: 1788–1830, 2011. 2. Tapson VF: Thrombolytic therapy in acute pulmonary embolism. Curr Opin Cardiol 27: 585–591, 2012. 3. Stein PD, Alnas M, Beemath A, Patel NR: Outcome of pulmonary embolectomy. Am J Cardiol 99: 421–423, 2007. 4. Dauphine C, Omari B: Pulmonary embolectomy for acute massive pulmonary embolism. Ann Thorac Surg 79: 1240–1244, 2005. 5. Kürkciyan I, Meron G, Sterz F, et al: Pulmonary embolism as a cause of cardiac arrest: Presentation and outcome. Arch Intern Med 160: 1529–1535, 2000.
283
6. Niwa A, Nakamura M, Harada N, Musha T: Observational investigation of thrombolysis with the tissue-type plasminogen activator monteplase for acute pulmonary embolism in Japan. Circ J 76: 2471–2480, 2012. 7. Fukuda I, Taniguchi S, Fukui K, Minakawa M, Daitoku K, Suzuki Y: Improved outcome of surgical pulmonary embolectomy by aggressive intervention for critically ill patients. Ann Thorac Surg 91: 728–732, 2011. 8. Takahashi H, Okada K, Matsumori M, Kano H, Kitagawa A, Okita Y: Aggressive surgical treatment of acute pulmonary embolism with circulatory collapse. Ann Thorac Surg 94: 785–791, 2012. 9. Wu MY, Liu YC, Tseng YH, Chang YS, Lin PJ, Wu TI: Pulmonary embolectomy in high-risk acute pulmonary embolism: The effectiveness of a comprehensive therapeutic algorithm including extracorporeal life support. Resuscitation 84: 1365–1370, 2013. 10. Chen YS, Lin JW, Yu HY, et al: Cardiopulmonary resuscitation with assisted extracorporeal life-support versus conventional cardiopulmonary resuscitation in adults with in-hospital cardiac arrest: An observational study and propensity analysis. Lancet 372: 554–561, 2008. 11. Shin TG, Jo IJ, Sim MS, et al: Two-year survival and neurological outcome of in-hospital cardiac arrest patients rescued by extracorporeal cardiopulmonary resuscitation. Int J Cardiol 168: 3424–3430, 2013. 12. Sakamoto T, Asai Y, Nagao K, et al: Extracorporeal cardiopulmonary resuscitation for out-of-hospital cardiac arrest. Resuscitation 81: S62, 2010. 13. Sung K, Lee YT, Park PW, et al: Improved survival after cardiac arrest using emergent autopriming percutaneous cardiopulmonary support. Ann Thorac Surg 82: 651–656, 2006. 14. Shin TG, Choi JH, Jo IJ, et al: Extracorporeal cardiopulmonary resuscitation in patients with inhospital cardiac arrest: A comparison with conventional cardiopulmonary resuscitation. Crit Care Med 39: 1–7, 2011. 15. Hajbaghery MA, Mousavi G, Akbari H: Factors influencing survival after in-hospital cardiopulmonary resuscitation. Resuscitation 66: 317–321, 2005. 16. Matos RI, Watson RS, Nadkarni VM, et al; American Heart Association’s Get With The Guidelines–Resuscitation (Formerly the National Registry of Cardiopulmonary Resuscitation) Investigators: Duration of cardiopulmonary resuscitation and illness category impact survival and neurologic outcomes for in-hospital pediatric cardiac arrests. Circulation 127: 442–451, 2013.
Management of Cardiac Arrest Caused by Acute Massive Pulmonary Thromboembolism: Importance of Percutaneous Cardiopulmonary Support Yang Hyun Cho,* Wook Sung Kim,* Kiick Sung,* Dong Seop Jeong,* Young Tak Lee,* Pyo Won Park,* and Duk-Kyung Kim†
Cardiac arrest caused by acute pulmonary embolism is associated with high patient mortality. We reviewed patients who had cardiac arrest caused by acute pulmonary embolism. Between January 2001 and September 2013, we identified 20 patients at our institution with a confirmative diagnosis of acute pulmonary thromboembolism and cardiac arrest. Percutaneous cardiopulmonary support (PCPS) and surgical embolectomy are the standard course of care for patients with shock or cardiac arrest caused by pulmonary thromboembolism at our institution. Patients were divided into two groups (PCPS group and non-PCPS group). Percutaneous cardiopulmonary support was used in 60% of patients. Surgical embolectomy was performed for 85% of patients. Overall in-hospital and surgical mortalities were 35% and 29%, respectively. On the basis of the multivariate analysis, both cardiopulmonary resuscitation more than 15 minutes and absence of PCPS were significant risk factors affecting survival (p = 0.001 and 0.049, respectively). When the duration of cardiac arrest is short, surgical embolectomy is a viable option after cardiac arrest caused by pulmonary thromboembolism. Percutaneous cardiopulmonary support may be a useful tool for both stabilizing the patient and providing a bridge when deciding on further management options. ASAIO Journal 2014; 60:280–283.
most effective method to treat PTE, it is usually performed when other modalities have failed or are contraindicated.1,2 One of the primary reasons contributing to the lower prevalence of surgical embolectomy is a surgical mortality rate as high as 20–30%.3,4 Indeed, reviews of data on surgical mortality after embolectomy include a number of high-risk situations including cardiac arrest and cardiopulmonary collapse, and the mortality of surgical embolectomy in such circumstances is reported as more than 50%.4–6 Percutaneous cardiopulmonary support (PCPS), which involves the use of extracorporeal membrane oxygenation (ECMO), has been suggested as a bridge-to-surgical embolectomy by some authors.7–9 Percutaneous cardiopulmonary support is also used as a part of cardiopulmonary resuscitation (CPR) in some centers, including our hospital.10–12 We have previously reported our use of extracorporeal CPR to assist conventional CPR,13,14 and emergent surgical embolectomy with or without PCPS is our preferred method to treat patients with acute massive PTE. In this retrospective study, we hypothesized that the use of PCPS is an important predictor of prognosis and surgical outcome for these patients.
Key Words: pulmonary embolism, extracorporeal membrane oxygenation, cardiac arrest, surgical embolectomy, cardiopulmonary resuscitation
Between January 2001 and September 2013, we identified 176 patients with acute massive or submassive PTE at Samsung Medical Center. A total of 20 patients (11%) who experienced cardiac arrest at initial presentation or after diagnosis of PTE were included in this study. Percutaneous cardiopulmonary support was performed in 12 patients (60%, PCPS group) to assist CPR or stabilize patients after recovery of spontaneous circulation (ROSC). Exclusion criteria were nonsurvivors of CPR, out-of-hospital cardiac arrest, and no evidence of PTE in imaging studies such as computed tomography, fluoroscopic angiography, and echocardiography. We divided patients into two groups, PCPS group and non-PCPS group (n = 8, 40%). Medical records for patients in each group were reviewed. The Samsung Medical Center Institutional Review Board approved this study and waived the need for patient consent.
Methods Study Subjects
Treatment modalities for acute massive pulmonary thromboembolism (PTE) consist of systemic anticoagulation, thrombolysis, catheter-based fragmentation and embolectomy, and surgical embolectomy. Although surgical embolectomy is the
From the *Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea; and †Department of Internal Medicine, Division of Cardiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. Submitted for consideration November 25, 2013; accepted for publication in revised form February 18, 2014. Disclosures: The authors have no conflicts of interest to report. Reprint Requests: Wook Sung Kim, MD, Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Korea. Email: [email protected]. Copyright © 2014 by the American Society for Artificial Internal Organs
CPR and PCPS The rapid response team of our institution calls the ECMO team when CPR is performed for more than 10 minutes or when a patient’s vital signs are unstable after ROSC. The leader of the ECMO team is a cardiovascular surgeon or interventional cardiologist. Percutaneous cardiopulmonary support
DOI: 10.1097/MAT.0000000000000063
280
281
CARDIAC ARREST BY PULMONARY THROMBOEMBOLISM
was established to terminate conventional CPR or maintain stable hemodynamics. We did not perform PCPS if the patient is stable after ROSC without recurrent cardiac arrest. The Capiox Emergency Bypass System (Terumo, Tokyo, Japan) or Prolonged Life Support System (Maquet Cardiopulmonary AG, Hirrlingen, Germany) was used in all cases. Two cannulae through the femoral artery and vein were inserted by Seldinger’s technique. A catheter was inserted into the superficial femoral artery to facilitate distal limb perfusion if needed. Anticoagulation was accomplished by a bolus injection of unfractionated heparin, followed by a continuous intravenous infusion of heparin to maintain an activated clotting time between 150 and 200 seconds. The flow rate was set to maintain a mean arterial pressure greater than 60 mm Hg. Cardiac arrest occurred in the operating room for seven patients. In these cases, the chest was opened directly and a standard cardiopulmonary bypass was performed while chest compressions and manual cardiac massage were performed. Surgical Pulmonary Artery Embolectomy At our institution, surgical embolectomy is the preferred method for management of acute massive PTE when the patient is in refractory shock or cardiac arrest. Surgery was performed whenever there was some chance of survival. Standard median sternotomy and cardiopulmonary bypass were performed. We removed all emboli up to the segmental pulmonary arteries. A brief period of circulatory arrest was encountered in five patients (median time of 4 minutes, range 1–35). Patients were able to be weaned off PCPS intraoperatively in all cases. Concomitant procedures were intracardiac thrombi removal (n = 2) and tricuspid annuloplasty (n = 1). Statistical Analysis Continuous variables were expressed as the mean ± standard deviation or median with interquartile range where appropriate. Continuous and categorical variables were compared using the Mann–Whitney U test or Fisher’s exact test, respectively. A multivariate cox regression model with model selection using forward stepwise method was used to identify risk factors for survival. Variables used for model selection were female, age, hypertension, diabetes mellitus, malignancy, CPR duration of more than 15 minutes, PCPS, thrombolysis, and surgical thrombectomy. A Kaplan–Meier curve was generated to show the trend
of midterm survival, and a log-rank test was used to compare survival curves between the groups. SPSS version 21.0 (SPSS Inc., Chicago, IL) was used for statistical analysis. A two-tailed p value of less than 0.05 was considered statistically significant. Results Patient Characteristics and Resuscitation The diagnosis of pulmonary embolism was made by computed tomography (n = 16, 84%), fluoroscopic angiography (n = 2, 11%), and transesophageal echocardiography (n = 1, 5%). All patients experienced cardiac arrest in the hospital. Cardiac arrest occurred in the operating room while preparing for surgical embolectomy in seven patients. Percutaneous cardiopulmonary support was used as a part of CPR or to stabilize the patient after ROSC in 12 patients (60%). Reasons for terminating CPR were ROSC (n = 13, 68%), initiation of PCPS (n = 4, 21%), or commencement of cardiopulmonary bypass in the operating room (n = 2, 11%). The most common predisposing cause of PTE was immobilization (58%). Three patients had thrombolysis for treatment of PTE and subsequently experienced cardiac arrest. There were no statistically significant parameters for patient survival except duration of CPR. Details of patient profiles are shown in Table 1. Surgical Embolectomy and Clinical Outcomes Surgical embolectomy was performed in 16 patients (84%). All patients with CPR duration of 15 minutes or less had surgery, whereas six of nine patients (67%) with CPR duration of more than 15 minutes underwent surgery. In three patients, surgical embolectomy was withheld, because it was thought to be futile. There were five in-hospital mortalities (31%) after surgical embolectomy. The in-hospital mortality after surgery was 0% in CPR duration of 15 minutes or less and 78% in CPR duration of more than 15 minutes. Causes of death were inability to be weaned from cardiopulmonary bypass (n = 2, 40%), anoxic brain damage (n = 2, 40%), and multiple organ failure (n = 1, 20%). Two patients had mediastinal re-exploration for postoperative bleeding (13%). History of hypertension, CPR lasting more than 15 minutes, and no use of PCPS were risk factors affecting the overall survival according to the multivariate analysis (Table 2 and Figure 1).
Table 1. Patient Characteristics Variables Female (%) Mean age, years (SD) Hypertension Diabetes mellitus Pregnancy related Immobilization Malignancy Duration of CPR, minutes (SD) Thrombolysis Surgical embolectomy CPB time (min)
Total
PCPS Group n = 12
Non-PCPS Group n=8
p
12 (60%) 57.81 (18.303) 9 (45%) 9 (45%) 3 (15%) 12 (60%) 4 (20%) 19.32 (17.531) 3 (15%) 17 (85%) 126.4 (65.202)
6 (50%) 60 (20.14) 6 (50%) 6 (50%) 1 (8%) 8 (67%) 3 (25%) 20.25 (17.884) 2 (17%) 9 (75%) 105 (24.885)
6 (75%) 54.53 (15.853) 3 (38%) 3 (38%) 2 (25%) 4 (50%) 1 (13%) 16.13(17.431) 1 (13%) 8 (100%) 153.86 (90.753)
0.373 0.418 0.67 0.67 0.537 0.648 0.619 0.462 1.000 0.242 0.873
CPB, cardiopulmonary bypass; CPR, cardiopulmonary resuscitation; SD, standard deviation; PCPS, percutaneous cardiopulmonary support.
282 CHO et al. Table 2. Multivariate Analysis of Risk Factors for Survival Variables Hypertension CPR duration >15 minutes PCPS
p
Hazard Ratio (95% CI)
0.029 0.001
7.701 (1.231–48.184) 54.743 (5.175–579.114)
0.049
0.226 (0.051–0.992)
CI, confidence interval; CPR, cardiopulmonary resuscitation; PCPS, percutaneous cardiopulmonary support.
There were 13 survival to-discharges, and the overall in-hospital mortality was 35%. All patients with CPR duration of 15 minutes or less were discharged without significant disability. Two patients with CPR duration of more than 15 minutes had significant neurologic damage. A 51-year-old man underwent CPR for 23 minutes, and after stabilization with PCPS, we performed surgical embolectomy. During the early postoperative stage, he exhibited severe neurologic dysfunction; however, he recovered significantly and displayed only mild cognitive dysfunction. A 40-year-old man whose CPR time was 24 minutes had PCPS during extracorporeal CPR. While preparing for emergent surgery, he had myoclonic status epilepticus, and thus the surgery was not performed and he was able to be weaned off PCPS after 2 days. At the time of the last follow-up, the patient remained in a vegetative state. Discussion In instances of cardiac arrest, surgical embolectomy is usually considered as a first-line treatment because it promptly resolves obstruction. Thus, this surgery is often performed in devastating situations. Despite a lack of clear evidence, current guidelines recommend surgical embolectomy if thrombolysis is contraindicated or fails.1,2 The high surgical mortality of embolectomy is considered an inevitable result of perioperative conditions such as cardiac arrest.4 In this study, we did not observe any mortality in patients whose CPR duration was 15 minutes or less. On the contrary, the in-hospital mortality of surgical embolectomy was high (78%) in patients who
underwent CPR for more than 15 minutes. Although the mortality rate of the prolonged CPR group was similar to previously reported rates, we observed a favorable outcome in patients who had a shorter duration of CPR.15,16 Thus, we believe that surgical embolectomy is still a valid option in patients who have had a short period of cardiac arrest. Duration of CPR is recognized as a universally important predictor of morbidity and mortality; however, it may be more prominent in PTE.5,15 Indeed, because the reasons for cardiac arrest in PTE include mechanical obstruction of pulmonary circulation, conventional CPR may not be as effective as in other situations. Our results suggest that prevention of cardiac arrest and reduction of CPR duration may be important for improving the outcome of PTE. Niwa et al.6 found that 11% of acute massive or submassive PTE patients experience cardiac arrest or cardiopulmonary collapse, and that the 30-day mortality of these patients is 59%. Therefore, early surgery and liberal use of PCPS may be useful for preventing catastrophic events and improving clinical outcomes. Several centers including our own hospital have recently begun to use PCPS as a part of CPR.10,11,13 Because PCPS is a partial cardiopulmonary bypass, it is effective for stabilizing patients and protects the right ventricle from the occluded pulmonary artery. Percutaneous cardiopulmonary support also can provide sufficient amounts of oxygen to the body. We have an in-house PCPS team that covers cardiac arrest without ROSC for 10 minutes. Use of PCPS improved survival in our study population. Despite prolonged CPR, there were two survivors who had PCPS-assisted resuscitation. Specifically, one patient whose duration of CPR was 23 minutes had PCPS and underwent emergent surgical embolectomy and was successfully discharged with only mild cognitive dysfunction. Conversely, another survivor had CPR for 24 minutes after which PCPS was inserted. The patient did not undergo surgery because of status epilepticus and experienced permanent severe anoxic brain damage. It is rarely necessary to perform emergent surgical embolectomy when PCPS is used, as it allows for additional time to make a decision regarding the course of action for a patient. Therefore, the role of PCPS in cardiac arrest caused
Figure 1. Kaplan–Meier survival curves for cardiac arrest after pulmonary thromboembolism according to (A) the duration of cardiopulmonary resuscitation (CPR) and (B) use of percutaneous cardiopulmonary support (PCPS). Although PCPS did not showed survival benefit in this univariate analysis, the most effective way to reduce duration of CPR is PCPS.
CARDIAC ARREST BY PULMONARY THROMBOEMBOLISM
by PTE is not only to stabilize the patient but also to provide a bridge when deciding further treatment options. Our study comprised a small number of patients and was retrospective in nature and thus may have been influenced by these limitations. Because cardiac arrest by proven acute PTE is rare, a multicenter study may be necessary. Our study does not directly suggest the usage of either surgical embolectomy or PCPS. Furthermore, although our results indicated a clear effect of CPR duration on survival, a larger scaled and randomized trial is necessary to verify these results. In conclusion, surgical embolectomy was found to be effective in patients where CPR was performed for a short duration due to acute PTE. Surgery was associated with a higher rate of mortality when CPR was performed for more than 15 minutes. Last, PCPS may be a useful tool for both patient stabilization and providing a bridge when deciding on further management options. References 1. Jaff MR, McMurtry MS, Archer SL, et al; American Heart Association Council on Cardiopulmonary, Critical Care, Perioperative and Resuscitation; American Heart Association Council on Peripheral Vascular Disease; American Heart Association Council on Arteriosclerosis, Thrombosis and Vascular Biology: Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: A scientific statement from the American Heart Association. Circulation 123: 1788–1830, 2011. 2. Tapson VF: Thrombolytic therapy in acute pulmonary embolism. Curr Opin Cardiol 27: 585–591, 2012. 3. Stein PD, Alnas M, Beemath A, Patel NR: Outcome of pulmonary embolectomy. Am J Cardiol 99: 421–423, 2007. 4. Dauphine C, Omari B: Pulmonary embolectomy for acute massive pulmonary embolism. Ann Thorac Surg 79: 1240–1244, 2005. 5. Kürkciyan I, Meron G, Sterz F, et al: Pulmonary embolism as a cause of cardiac arrest: Presentation and outcome. Arch Intern Med 160: 1529–1535, 2000.
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