HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hirose, H. Articles by Nagano, N. Search for Related Content PubMed PubMed Citation Articles by Hirose, H. Articles by Nagano, N.

Ann Thorac Surg 2000;69:425-428
© 2000 The Society of Thoracic Surgeons

---

Original Articles

Surgical management of unstable patients in the evolving phase of acute myocardial infarction

^a Department of Cardiovascular Surgery, Shin-Tokyo Hospital, Chiba, Japan

Address reprint requests to Dr Hirose, Department of Cardiovascular Surgery, Shin-Tokyo Hospital, 473-1 Nemoto, Matsudo City, Chiba 271-0077, Japan
e-mail: genex{at}idt.net

	Abstract

Top Abstract Introduction Patients and methods Results Comment References

 
Background. Acute myocardial infarction (AMI) can be treated with thrombolysis or coronary catheter intervention; surgical treatment—coronary artery bypass grafting (CABG)—is reserved for the patients in whom other procedures have failed. We performed CABG in 47 patients during the evolving phase of AMI, and analyzed their short-term and long-term results.

Methods. Preoperative, intraoperative, and postoperative data were analyzed in patients who underwent emergency CABGs for AMI between January 1, 1992, and July 31, 1998. CABGs performed more than 7 days after AMI were excluded from this study.

Results. The subjects were 47 patients (33 males and 14 females) with AMI who were treated by emergency CABG. Intraaortic balloon pumping was used in 44 cases and percutaneous circulatory pulmonary support was used in 3 cases. The mean interval between the onset of AMI and surgery was 27.4 ± 27.9 hours. The mean number of bypass grafts was 3.0 ± 1.1, and at least 1 arterial conduit was used in 45 cases (95.7%). Aortic clamp time, pump time, and operative time were 64.7 ± 31.7, 117.3 ± 55.2, and 313.2 ± 84.8 minutes, respectively. IABP or percutaneous cardiopulmonary support were removed in the intensive care unit (ICU) 30.0 ± 28.9 hours after CABG. The patients were extubated 41.4 ± 40.5 hours after surgery, remained in ICU for 4.7 ± 2.7 days, and were discharged from the hospital after 27.0 ± 22.5 days. Three patients died from multiorgan failure related to postoperative sepsis, and 8 cases of major complications were observed. The actuarial 5-year survival rate of the patients treated with CABG was 83.0%.

Conclusions. Surgical treatment in the unstable patients after AMI can be performed with acceptable risk. Arterial revascularization may contribute to improvement in long-term results.

	Introduction

Top Abstract Introduction Patients and methods Results Comment References

 
Thrombolytic therapy and angioplasty have contributed to the reduction of mortality in acute myocardial infarction (AMI) [1]. Surgical intervention for the acute phase of AMI is indicated for patients with refractory hypotension despite intensive medical care, including the use of intraaortic balloon pumping (IABP) and percutaneous circulatory pulmonary support (PCPS). Difficulty or failure of catheter intervention due to left main disease, three vessel disease, or other contraindication for catheter treatment is also managed by surgery. The delay of the early surgical or medical treatment for AMI may result in development of intravascular thrombus or coronary spasm followed by extension of myocardial necrosis. Once the extension of the infarcted area occur, the mortality is known to increase fourfold [2]. In most of the cases, coronary artery bypass grafting (CABG) is reserved for the patients in whom other treatments have failed [3]. We analyzed our experiences of emergency CABG in the evolving phase of AMI (less than 1 week after onset of AMI), and outlined their short-term and long-term outcomes.

	Patients and methods

Top Abstract Introduction Patients and methods Results Comment References

 
Among 1,564 CABGs performed at Shin-Tokyo Hospital between January 1, 1992, and July 31, 1998, patients who underwent emergency CABGs for AMI were retrospectively analyzed. CABGs performed more than 7 days after AMI were excluded from this study. AMI was defined as elevated cardiac isoenzymes (at least 4.0% MB fraction), EKG change, and angiographic evidence of acute coronary occlusion. Catheter related acute coronary occlusions were included in this study. Cardiogenic shock was defined as the presence of two or more of the following parameters: systolic pressure less than 80 mm Hg, cardiac index less than 2.1 L/min, urinary output less than 20 mL/hour, or clinical evidence of diminished cerebral perfusion. IABP was usually inserted in the catheterization laboratory before coronary angiography if at least one previously mentioned criterion for shock was presented, or if angina could not be controlled by medication. PCPS (CAPIOX, Termo Co, Tokyo, Japan) was initiated if patients exhibited profound shock and refractory ventricular arrhythmia, and was allow to run at a flow rate of 3.5 L/min (about one-fourth of the calculated optimal flow).

Emergency surgery was performed for refractory cardiogenic shock, despite inotropic support and IABP support, for persistent angina despite maximal medication including drip infusion of coronary dilators and inotropics, or for catheter-related AMI.

Forty-six of 47 patients underwent CABG with cardiopulmonary bypass (CPB), and 1 received off-pump CABG on the beating heart. The cardiopulmonary bypass was run at normothermia (36°C). Warm blood cardioplegic arrest was used for all cases, and given through either antegrade, retrograde, or both.

Preoperative data (age, sex, presence of shock, location of infarctions, coronary lesions, and the use of cardiac support systems), intraoperative (materials of grafts, number of bypasses, cross-clamp time, cardiopulmonary bypass time, and operating time), and postoperative data (intubation period, length of stay in intensive care unit [ICU] and ward, and complications) were analyzed. The current status of the patients was determined by personal phone call.

Results were expressed as mean ± standard deviation. The survival curve was obtained using the Kaplan-Meier method.

	Results

Top Abstract Introduction Patients and methods Results Comment References

 
Forty-seven patients (33 males and 14 females, with a mean age of 63.5 ± 11.8 years) with AMI were treated by emergency CABGs. Before the emergency CABGs, percutaneous transluminal angioplasty (PTCA) was performed in 15 (31.9%) patients, and thrombolysis was performed in 8 (17.0%) patients. Eight patients exhibited catheter-related AMIs, including 4 cases of coronary dissection after PTCA and 4 cases of acute stent occlusion. The location of the infarctions was anteroseptal in 32 (68.1%), inferior in 12 (25.5%), and posterolateral in 2 (4.3%) patients. All patients underwent coronary catheterization and were found to have an average of 2.3 ± 0.6 diseased coronary arteries, including 18 cases (38.3%) of the left main trunk disease, 9 cases (19.1%) of single vessel disease, 16 (34.0%) of double vessel disease, and 22 cases (46.8%) of triple vessel disease. Cardiogenic shock was presented in 19 cases (40.2%). IABP was used in 44 cases (93.6%) and PCPS was used in 3 cases (6.4%). Only 3 patients (6.4%) were free from any types of cardiac support devices. The indications for emergency CABG included profound shock in 19, catheter-related AMI in 8, and failure or impending failure of medical therapy in 27 cases.

The mean interval between the onset of AMI and surgery was 27.4 ± 27.9 hours (2 to 120 hours). Nineteen out of forty-seven patients (40.2%) underwent emergency CABGs within 12 hours after the onset of AMI, and 13 of 47 (27.5%) between 13 and 24 hours. The remaining 15 of 47 (31.9%) were treated between 25 and 120 hours after the onset, and most patients who underwent surgery more than 25 hours after the onset were transferred from other hospitals. The patient with the longest interval (120 hours) between the onset and CABG was first treated medically at a local hospital. This patient was weaned off IABP once, and then refractory congestive heart failure associated with acute renal failure developed. A second IABP was inserted, and the patient was transferred to our hospital for CABG.

The mean number of bypass grafts was 3.0 ± 1.1. At least one arterial conduit, such as the left internal mammary artery (43 of 47, 91.5%), the right internal mammary artery (9 of 47, 19.1%), the right gastroepiploic artery (9 of 47, 19.1%), or the radial artery (11 of 47, 23.4%) was used in 44 cases (93.6%). A saphenous vein graft was used in 36 cases (76.6%); however, total saphenous vein bypass was limited to 3 cases (6.3%) that exhibited advanced peripheral artery disease. Aortic clamp time, pump time, and operative time were 64.7 ± 31.7, 117.3 ± 55.2, and 313.2 ± 84.8 minutes, respectively. Nineteen (40.4%) CABGs were performed without blood transfusion.

In 44 patients who had IABP and PCPS preoperatively, 11 were removed in the ICU immediately after CABG, 23 were weaned and removed within 24 hours, and 35 within 48 hours. The mean duration of using cardiac assist devices was 30.0 ± 28.9 hours. The patients were extubated 41.4 ± 40.5 hours (4 to 152 hours) after CABG, remained in ICU for 4.7 ± 2.7 days (2 to 14 days), and were discharged from the hospital after 27.0 ± 22.5 days (11 to 131 days).

There were 3 hospital deaths, resulting in a mortality rate of 6.4%. One patient developed sepsis secondary to bowel infarction, and the remaining 2 mortalities were from acute renal failure that progressed into multiorgan failure and sepsis. These 3 patients showed preoperative shock, triple vessel disease, advanced age (> 65), and a longer aortic cross-clamp time and CPB time than the average patient. The mortality rate in the patients with preoperative shock, triple vessel disease, age older than 65 was 3 of 19 (15.8%), 3 of 22 (13.6%), and 3 of 22 (13.6%), respectively. Major complications were observed in 8 patients, resulting in a morbidity rate of 17.0% and included 3 renal failures requiring hemodialysis, 2 cerebral vascular accidents, 1 late ventricular septal perforation, 1 respiratory failure requiring reintubation, and 1 wound dehiscent requiring a flap. During the 2.3 ± 1.7 year follow-up, there was 1 remote cardiac death, 1 sudden death, and 2 noncardiac deaths. The actuarial 5-year survival rate was 83.0%, including hospital mortality (Fig 1).

View larger version (14K): [in this window] [in a new window]   Fig 1. Survival curve of patients with acute myocardial infarction treated by emergency coronary artery bypass grafting (n = 47) obtained by the Kaplan-Meier method. The actuarial 5-year survival rate was 83.0% with 2.3 ± 1.7 year follow-up (maximum follow-up 6.8 years and minimum follow-up 0.7 years). There was 1 remote cardiac death, 1 sudden death, and 2 non-cardiac deaths. The calculated 5-year survival rate was 84.7%, including hospital mortality.

	Comment

Top Abstract Introduction Patients and methods Results Comment References

The long-term survival after surgical intervention in our series with a mean follow-up of 2.3 years and a maximum follow-up of 7.3 years was 83.0%. This long-term survival rate is comparable to a larger study reported by Every and colleagues [9]; however, their patient population had lower risks than ours (cardiogenic shock was present in only 1.7% of patients in their study, compared to 40.2% in our series). In other recent studies on surgery for AMI, 5-year survival rates of 70% to 75% [4] and 55% have been reported [10]. One explanation for our favorable outcome is the frequent use of internal mammary arteries and other arterial conduits. Follow-up of the patients with AMI treated with CABG using the internal mammary artery was reported by Kaul and coworkers [4] and their 5-year survival rate was 89%, which was comparable with our study. In our practice, total saphenous vein grafting was employed only when all arterial conduits were of poor quality, including the internal mammary, radial, and gastroepiploic arteries. It may be difficult to harvest arterial conduits in an AMI setting; however, the long-term patency of arterial grafts is known to be superior to saphenous vein grafts [11–13], and the time required for harvesting arteries may be negligible considering the entire operation. Expectedly, one of the remote cardiac death cases in our study had received only saphenous vein bypasses.

Profound shock by AMI is most likely because of mechanical pump failure by massive myocardial dysfunction. IABP may play a role in maintaining the hemodynamics; however, if profound shock exists, only surgical repair can save the patient’s life. Revascularization of the coronary flow distal to the occluded vessels will save the myocardium from the impending infarction and prevent further extension of the infarcted area. Persistent angina following AMI may be a sign of impending infarction in the border-zone, most likely from reduced coronary blood supply from the collaterals. As we previously discussed, patients who develop AMI usually exhibit other stenotic coronary segments (in another words, multivessel disease) in addition to the original occluded artery. Revascularizing these stenotic arteries is important to prevent future development of AMI and sudden death.

The timing of CABG after AMI is controversial, even though CABG can provide a better outcome in patients with AMI than medical treatment [8, 9]. We had no hospital mortality among the patients who underwent emergency CABG within 24 hours after the onset of AMI, despite the fact that 14 patients (43.8%) had triple vessel disease and 11 patients (34.4%) were in cardiogenic shock. Patients with shock should be treated with primary CABG under IABP support instead of spending a lot of time in the coronary catheter laboratory. Primary PTCA and other coronary catheter interventions play roles to optimize coronary blood flow; however, once these procedures fail or are expected to fail because of triple vessel disease, left main lesions, and jeopardized collateral flow, surgical revascularization must be carried out without delay to prevent further extension of the infarction, which may result in severe pump failure.

In summary, we reported a series of emergency CABGs in evolving phase of AMI, with the short- and long-term results. The condition of those who referred to surgical intervention were very often unstable. Among these unstable patients undergoing emergency CABG, preoperative shock, severe multivessel disease, and advanced age are risk factors for perioperative death. Early surgical treatment should be conducted without hesitation if medical treatment is not successful. Under these circumstances, full revascularization using arterial conduits plays a key role for improvement in survival.

	References

Top Abstract Introduction Patients and methods Results Comment References

 

1. Grines C.L., Browne K.F., Marco J., et al. primary angioplasty in myocardial infarction study group. A comparison of immediate angioplasty for acute myocardial infarction. N Engl J Med 1993;328:673-679.[Abstract/Free Full Text]
2. Jones E.L., Waites T.F., Craver J.M., et al. Coronary bypass for relief of persistent pain following acute myocardial infarction. Ann Thorac Surg 1981;32:33-43.[Abstract]
3. Honye J., Satio S., Kanmatsuse K. Conservative management in patients with acute coronary syndrome. J Cardiol 1999;33(Suppl I):31.
4. Kaul T.K., Fields B.L., Riggins S.L., Dacumos G.C., Wyatt D.A., Jones C.R. Coronary artery bypass grafting within 30 days of an acute myocardial infarction. Ann Thorac Surg 1995;59:1169-1176.[Abstract/Free Full Text]
5. Lee J.H., Murrell H.K., Strony J., et al. Risk analysis of coronary bypass surgery after acute myocardial infarction. Surgery 1997;122:675-681.[Medline]
6. Berg R., Jr, Selinger S.L., Leonard J.J., Grunwald R.P., O’Grady W.P. Immediate coronary artery bypass for acute evolving myocardial infarction. J Thorac Cardiovasc Surg 1981;81:493-497.[Abstract]
7. Phillips S.J., Kongtahworn C., Skinner J.R., Zeff R.H. Emergency coronary artery reperfusion. J Thorac Cardiovasc Surg 1983;86:679-688.[Abstract]
8. Hochberg M.S., Parsonnet V., Gielchinsky I., Hussain S.M., Fisch D.A., Norman J.C. Timing of coronary revascularization after acute myocardial infarction; early and late results in patients revascularized within seven weeks. J Thorac Cardiovasc Surg 1984;88:914-921.[Abstract]
9. Every N.R., Maynard C., Cochran R.P., Martin J., Weaver W.D., myocardial infarction triage and intervention investigators. Characteristics, management, and outcome of patient with acute myocardial infarction treated with bypass surgery. Circulation 1996;94(9 Suppl):II81-II86.
10. Yamagishi I., Sakurada T., Abe T. Emergency coronary artery bypass grafting after acute myocardial infarction. What influenced early postoperative mortality?. Ann Thorac Cardiovasc Surg 1998;4:28-33.[Medline]
11. Loop F.D., Lytle B.W., Cosgrove D.M., et al. Influence of the internal mammary artery graft on 10 year survival and other cardiac events. New Engl J Med 1986;314:1-6.[Abstract]
12. Suma H., Amano A., Horii T., Kigawa I., Fukuda S., Wanibuchi Y. Gastroepiploic artery graft in 400 patients. Eur J Cardiothorac Surg 1996;10:6-11.[Abstract]
13. Buxton B.F., Fuller J.A., Tatoulis J. Evolution of complete arterial grafting for coronary artery disease. Tex Heart Inst J 1998;25:17-23.[Medline]

This article has been cited by other articles:

				J. M. Albes, M. Gross, U. Franke, J. Wippermann, T. U. Cohnert, R. Vollandt, and T. Wahlers Revascularization during acute myocardial infarction: risks and benefits revisited Ann. Thorac. Surg., July 1, 2002; 74(1): 102 - 108. [Abstract] [Full Text] [PDF]

				D. A. Zvara Treatment of Perioperative Myocardial Ischemia Seminars in Cardiothoracic and Vascular Anesthesia, July 1, 2001; 5(2): 166 - 183. [Abstract] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hirose, H. Articles by Nagano, N. Search for Related Content PubMed PubMed Citation Articles by Hirose, H. Articles by Nagano, N.