Use of internal mammary artery for emergency grafting after failed coronary angioplasty

Use of Internal Mammary Artery for Emergency Grafting After Failed Coronary Angioplasty Frank L. Caes, MD, and Guido J. Van Nooten, MD Department of Cardiac Surgery, University Hospital, Ghmt, Belgium

Of 929 consecutive patients who underwent percutaneous transluminal coronary angioplasty over a 36-month period, 32 (3.4%) had emergency coronary artery bypass grafting for angioplasty failure. Twenty-two patients (69%) were hemodynamically stable (stable group), and 10 (31%)were unstable (unstable group) before emergency bypass. In the unstable group, the interval between failed angioplasty and opening of the grafts or end of extracorporeal circulation was significantly shorter (p < 0.001 and p < 0.002, respectively) and significantly more grafts per patient were performed ( p < 0.05) than in the stable group. Twenty-seven patients (84%) received at least one internal mammary artery graft, independent of their hemodynamic condition. In 11culprit left anterior descending arteries, the internal mammary artery

graft was supplemented by a saphenous vein graft to the same territory, especially in the unstable group. There were no hospital deaths. Postoperatively, the incidence of myocardial infarction ( p < 0.005) and the use of antiarrhythmics ( p < 0.0001) were increased and length of stay tended to be longer in the unstable compared with the stable group. The use of a reperfusion catheter had no influence on clinical outcome, except for a significantly reduced postoperative use of antiarrhythmics ( p < 0.05). The internal mammary artery can be used in emergency coronary artery bypass grafting after failed percutaneous transluminal coronary angioplasty, without hospital mortality and with acceptable morbidity, especially in hemodynamically stable patients. (Ann Thorac Surg 1994;57:1295-9)

I

The ischemic process was considered to start when the cardiologist recognized the PTCA failure. At this time, the patient either underwent further attempts at reopening the culprit vessel or was sent immediately to the operating room after consultation of the surgeon. During most PTCA procedures, operating room facilities and personnel were kept on standby. Revascularization was performed with standard techniques during cardiopulmonary bypass, with a membrane oxygenator, under moderate systemic hypothermia, and using antegrade, retrograde, or both types of crystalloid cardioplegic cardiac arrest. The IMA grafts were prepared in a standard fashion, under pharmacologic block of the stellate ganglion and application of external papaverine. Preparation of the IMA was always accomplished within 10 minutes. In some unstable patients, cardiopulmonary bypass was instituted before preparation of the IMA. All diseased vessels (with stenosis more than 50% of luminal diameter) were bypassed. No patient had a previous bypass operation. Patients were considered in hernodynamically unstable condition before CABG if they had cardiac arrest necessitating cardiopulmonary resuscitation, ventricular fibrillation or tachycardia, or hypotension of less than 80 mm Hg on vasopressors. Intraaortic balloon pumping was never used during PTCA or preoperatively. The diagnosis of perioperative myocardial infarction (MI) was made by the presence of new, persistent Q waves or substantial reduction in R waves, in conjunction with increases in serum glutamic-oxaloacetic transaminase greater than 100 IU/L and increases in creatine kinase-MB fraction isoenzyme level of more than 10%. Statistical analysis was performed with the help of the

n the last decade, percutaneous transluminal coronary angioplasty (PTCA) has become an accepted treatment for patients with symptomatic coronary artery disease [l]. Despite improvements in technology and technique and growing experience, PTCA is not free of complications, although these have been decreasing in frequency [2]. A small but persistent subset of patients will require emergency coronary artery bypass grafting (CABG) for acute myocardial ischemia due to failed PTCA [3]. There has been great reluctance to use the internal mammary artery (Ih4A) as a bypass conduit in these emergency situations until recent years [4]. Nevertheless, significantly increased long-term graft patency [5] and associated improved late survival [6] in patients having CABG with use of the IMA, as opposed to the saphenous vein, have been demonstrated. This article reviews our experience with liberal use of the IMA in emergency CABG after failed PTCA.

Material and Methods From February 1990 through January 1993, 929 consecutive patients underwent PTCA and 32 of these (3.4%) required emergency revascularization for the treatment of acute ischemic complications of angioplasty. Their medical records were reviewed to determine preoperative clinical and angiographic variables, course of PTCA and subsequent CABG, and postoperative outcome. Accepted for publication Sep 24, 1993 Address reprint requests to Dr Caes, Department of Cardiac Surgery, University Hospital of Ghent, De Pintelaan 185, 5 9 0 0 0 Ghent, Belgium.

0 1994 by The Society of Thoracic Surgeons

0003-4975/94/$7.00

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Ann Thorac Surg 1994;57 1295-9

SYSTAT 5.2 program. Comparisons between groups were carried out using Pearson 2 analysis for categorical variables and Student's t test for continuous data. All values are given as mean standard deviation, and a p value of 0.05 or less was considered significant.

Table l . Comparison of Elapsed Ischemic Time and Duration of Emergency CABG in Stable and Unstable Patients After Failed PTCA"

Results

Interval

Preoperative characteristics of the 32 patients undergoing emergency CABG after failed PTCA are as follows:

Interval 223.5 f 84.3 139.2 rt 44.9 <0.001 197.1 :t 83.5 PTCA failureopening grafts Interval 246.7 f 86.3 167.7 f 44.5 <0.002 223.7 f 84 PTCA failure-end ECC Cross-clamp 20.0 f 9.1 25.7 f 10.3 NS 21.8 :i 9.7 time ECC 46.6 rt 12.4 73.2 f 39.1 NS 54.2 :t 25.8 duration

*

*

Age: mean standard deviation (range) (y) Medwomen Angina class I I1 I11 IV unstable Myocardial infarction recent prior Prior PTCA Cardiovascular risk factors Smoking Obesity Hyperlipidemia Type A behaviour Arterial hypertension Diabetes mellitus Heredity

59.2

* 8.3 (42-71) 2715

2 (6%) 8 (25%) 5 (16%) 11 (34%) 6 (19%) 2 (6%) 10 (31%) 2 (6%) 26 (81%) 12 (38%) 14 (44%) 15 (47%) 12 (38%) 5 (16%) 14 (44%)

Two patients had a history of recent MI: the first a 2-day-old anterior wall MI and the second an inferolateral MI with secondary extension, 5 and 3 weeks before PTCA, respectively. The majority of the patients presented with single- or double-vessel involvement and good left ventricular function. One case of double-vessel disease turned out to be a bad indication for PTCA because of concomitant left main involvement. In 4 patients, a PTCA of two vessels was attempted. The vessel affected by PTCA failure (culprit artery) was the left anterior descending artery (LAD) in nearly two thirds of the cases. Angiographic data were as follows: Vessel involvement Single Double Triple Left ventricular ejection fraction mean ? standard deviation <0.45 Left ventricular end diastolic pressure >20 mm Hg Culprit artery Left anterior descending Right coronary Circumflex coronary

17 (53%) 13 (41%) 2 (6%)

*

0.77 0.13 4 (13%) 5 (16%) 22 (69%) 9 (28%) 1(3%)

Vessel support of the culprit artery was achieved using a reperfusion catheter (ACS RX Perfusion; Advanced Car-

Time (min rt standard deviation) Stable group (n = 22)

Unstable group (n = 10)

p value

All patients (n = 32)

Values are shown as minutes f standard deviation ECC = extracorporeal circuCABG = coronary artery bypass grafting; lation; NS = not significant; PTCA = percutaneous transluminal coronary angioplasty; SD = standard deviation.

a

diovascular Systems Inc, Temecula, USA) in 12 patients. Ten of them remained hemodynamically stable until emergency CABG, while the other two had to be defibrillated because of ventricular fibrillation. A stent (Wiktor: Medtronic Inc, Minneapolis, MN) was placed in two cases of failed PTCA of the LAD. Despite previous intracoronary thrombolysis and heparinization, however, reocclusion occurred after 15 and 60 minutes, respectively, leading to severe hemodynamic instability and necessitating emergency CABG. In the other patients, recrossing d the culprit artery failed or was considered too difficult or time-consuming, and the patient was referred immediately for operation. Signs and symptoms of ischemia after PTCA failure included chest pain in 26 patients (81%)and new ST segment elevation in 23 patients (72%). Twentytwo patients (69%)were hemodynamically stable (stable group), and 10 patients (31%) were unstable (unstable group) prior to emergency CABG. Six of these unstable patients were in cardiogenic shock and 1 was undergoing cardiopulmonary resuscitation; all had undergone IPTCA of the LAD. Ventricular arrhythmias requiring cardioversion developed in 6 patients. The interval between failed PTCA and opening of the grafts or end of extracorporeal circulation at emergency CABG was significantly shorter in the unstable group than in the stable group. No significant difference was noted in aortic cross-clamp time or duration of extracorporeal circulation (Table 1). A single bypass graft was performed in 7 patients (22%),two bypass grafts in 14 patients (44%), and three or more in 11 patients (34%), for an average number of bypass grafts per patient of 2.2 k 0.8. IMA grafts were used in 27 patients (84%),including 2 cases (6%)of double IMA graft and 2 cases (6%)of sequential left IMA graft. The IMA was the graft of choice for the culprit artery in 23

CAES AND VAN NOOTEN IMA GRAFTING FOR FAILED PTCA

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patients (72%).In 11 culprit LAD patients, the left IMA graft to the LAD was supplemented by a saphenous vein graft to the same territory (9 to a diagonal branch and 2 to the LAD; Table 2). There was no significant difference in the use of IMA to bypass the culprit artery between the stable and unstable groups. In the latter group, a significantly higher number of grafts per patient was performed (Table 3). No IMA graft was performed in only 5 patients (16%).Two of these were taken directly to the operating room from the catheterization laboratory in cardiogenic shock, and required cardioversion for ventricular fibrillation. In the other 3 patients, presenting with a failed PTCA of the right coronary artery, the right IMA was considered inappropriate for emergency grafting of this vessel at the distal end or terminal branches. The interval between failed PTCA and opening of the grafts or end of ECC was similar regardless of whether the IMA was used. Postoperatively, there were no deaths. Overall, 14 patients (44%)sustained a perioperative MI by electrocardiographic and enzyme criteria. Compared with the stable group, the unstable group had a significantly higher incidence of perioperative MI ( p < 0.005). In the group of 23 patients undergoing IMA bypass to the culprit artery, a perioperative infarction was noticed in 10 patients (43%). Eighty percent of the unstable patients versus 50% of the stable patients required inotropic support postoperatively. A significantly increased usage of antiarrhythmics during initial postoperative phase was noted in the unstable group compared with the stable group (80% versus 5%; p < 0.0001). One 48-year-old unstable woman, who underwent a sequential left IMA graft to the diagonal branch and LAD and a saphenous vein graft to distal LAD, could not be weaned from extracorporealcirculation because of massive myocardial infarction, and had to be supported by a left ventricular assist device (centrifugal pump and intraaortic balloon pumping). Two days later she underwent a successful orthotopic heart transplantation, and is doing well now, more than 2 years later [7]. The incidence of other postoperative complications was comparable in the stable and unstable groups. In the latter group, mean length of stay in the intensive care unit and hospital tended to be longer, but not significantly. In 2 patients in this group, hospital time was prolonged to

Table 2. Use of lnternal Mammary Artery in Emergency CABG After Failed PTCA IMA Used Left IMA

Coronary Arterv Bvpassed

Culprit LAD Dx and culprit LAD sequentially Nonculprit LAD Nonculprit CX Right IMA Culprit RCA Double IMA Culprit LAD-nonculprit RCA Culprit RCA-nonculprit LAD

No. of Patients 17 2 3 1 2 1 1

CABG = coronary artery bypass grafting; CX = circumflex coronary IMA = internal mammary artery; artery; Dx = diagonal branch; LAD = left anterior descending; PTCA = percutaneous transluminal coronary angioplasty; RCA = right coronary artery.

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Table 3. Perioperative Characteristics of Stable and Unstable Emeraencu CABG Patients After Failed PTCA Characteristic

Stable Group (n = 22)

Unstable Group (n = 10)

p Value

All Patients (n = 32)

2.0 f 0.9 2.5 f 0.5 (0.05 2.2 f 0.8 No. of grafts (mean 5 SD) Graft for culprit artery IMA NS 23 (72%) 16 (73%) 7 (70%) 6 (27%) 3 (30%) SVG NS 9 (28%) Postoperative MI 14 (44%) 6 (27%) 8 (80%) <0.005 Inotropic 11 (50%) 8 (80%) NS 19 (59%) support Antiarrhythmics 1(5%) 8 (80%) <0.0001 9 (28%) IABP-LVAD 0 (0%) l(lO%) NS 1(3%) 2 (9%) 2 (6%) Reoperation O(O%) NS (bleeding) 1(5%) 2 (6%) 1(10%) NS Prolonged intubation (>24 h) Pneumothorax 2 (9%) O(O%) NS 2 (6%) Atrial fibrillation 5 (23%) 3 (30%) NS 8 (25%) Stemitis 0 (0%) l(lO%) NS 1(3%) Length of stay (days f SD) 2.8 2 2.5 8.1 f 16.8 In ICU NS 4.4 f 9.6 Total 11.4 2 4.9 21.5 f 25.2 NS 14.6 f 14.9 CABG = coronary artery bypass grafting; IABP = intraaortic balloon ICU = intensive care unit; IMA = internal mammary artery; pump; MI = myocardial infarction; LVAD = left ventricular assist device; PTCA = percutaneous transluminal coronary NS = not significant; SVG = saphenous vein angioplasty; SD = standard deviation; graft.

more than 1 month, due to sternitis and bridge to heart transplantation, respectively (Table 3). The use of a reperfusion catheter after failed PTCA was associated with a significant decrease in use of antiarrhythmics after subsequent CABG ( p < 0.05), but otherwise did not influence clinical outcome, incidence of myocardial infarction, or use of IMA graft (67% and 72% in patients treated with and without reperfusion catheter, respectively).

Comment Despite apparent improvements in technical success with PTCA, there is a persistent, although decreasing, subset of patients who will require emergency CABG for ischemic complications of failed PTCA. Although a collective review of the 1984 to 1989 period reported an incidence of emergency CABG for failed PTCA of 5% [3], we observed an emergency bypass rate of 3.4% in the present series, and even figures less than 3% have been noted during the last years [4, 8, 91. Thirty-one percent of the patients in our study were in unstable condition before emergency CABG. This is comparable with the incidence of hemodynamic instability

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reported by several authors [3, 10-121. In a recent study, however, the incidence of instability was only 9%, probably related to the fact that the culprit vessel could be stabilized more often by a guidewire or bailout catheter and the fact that the compromised ventricle was sometimes supported by intraaortic balloon pumping or cardiopulmonary assist [4]. In the present study, the average interval between failed PTCA and opening of the grafts at CABG was 197 minutes. This is slightly longer than the average times reported by others (range, 142 to 180 minutes), although diversity in defining ischemic time makes comparison difficult [3, 10, 12-14]. Moreover, in 12 of our patients, the use of a bailout catheter to reestablish coronary perfusion presumably reduced the ischemic period in the interval between failed PTCA and opening of the grafts. This interval was significantly shorter in the unstable group, indicating that the team was proceeding faster in those patients, who were often taken to operation directly from the catheterization laboratory. The reported incidence of perioperative MI after emergency CABG for failed PTCA ranges from 18% to 63%, with an average of 40%, consistent with our observations [3]. In the present study, hemodynamically unstable patients were found to be at increased risk for perioperative MI, a finding observed by others [13, 151. Several prior studies have identified multivessel disease [3, 131, multivessel PTCA [131, electrocardiographic changes immediately after PTCA [12-151, occurence of a new occlusion or further narrowing of the dilated vessel [ll], and insulin-dependent diabetes mellitus [15]as risk factors for perioperative MI; however, our data did not confirm these observations. Major complications, other than myocardial infarction, have been reported to occur in 11%to 50% of patients undergoing emergency CABG for failed PTCA [3, 9, 10, 14, 16, 171, consistent with our present observations. The 59% requirement of postoperative inotropic support in the present study is comparable to that noted by others [9, 161. Hemodynamically unstable patients had a higher incidence of requiring vasopressors (80% versus 50% for stable patients). Postoperative support by intraaortic balloon pumping has been reported in 4% to 32% of patients undergoing emergency CABG for failed PTCA [3, 9, 16181. Ventricular assist devices have been used after emergency CABG for failed PTCA only rarely [3, 7, 91, although most hospital deaths are associated with low cardiac output and inability to wean from cardiopulmonary bypass [3, 9, 14-15]. In the present study, only 1 patient could not be weaned from cardiopulmonary bypass, and had to be supported by a left ventricular assist device and intraaortic balloon pumping as a bridge to successful orthotopic heart transplantation. Antiarrhythmics were required soon after the operation in 28% of our patients, almost exclusively in the hemodynamically unstable group. The average length of hospital stay of 14.6 2 14.9 days observed in the present study is comparable to that reported by others [3,9, 161. The average length of stay in the intensive care unit and in the hospital tended to be longer for patients in the hemodynamically unstable

Ann Thorsic Surg 1994;571295-9

group compared with the stable group, but this did not reach statistical significance. Despite significantly increased long-term graft patency and associated improved late survival with the use of IMA versus saphenous vein grafts [5,6], most surgeons are reluctant to use the IMA in these emergency situations, because it is more time consuming and technically demanding to prepare, and ii may provide inadequate flow [19]. While most series of emergency CABG after failed PTCA exclusively used venous grafts, the use of IMA grafts by Pelletier [lo] (3%), Parsonnet [16] (9%), Golding [14] (19%), Sundram [20] (23%), Lazar [13] (25%), Borkon [9] (31%), Tobe [21] (40%), Zapolanski [4] (43%), Ferguson [22] (44%), and their associates was less than in our study (84%).Despite liberal use of IMA grafts, we had no hospital mortality, and a postoperative morbidity comparable to others,. We used the IMA to bypass the culprit vessel not only equally in the stable and unstable group (73% and 70%, respectively), but also equally in patients treated with or without the reperfusion catheter (67% versus 72%). To overcome any inadequate flow of the IMA, we often supplemented it with a venous graft to the same territory, especially in the unstable group (70% versus 18% in the stable group). This did not prolong the aortic crossclamp time significantly in the latter group. The potential influence of the competitive flow from this venous graft on the patency of the IMA placed to the same distribution remains uncertain, and should be evaluated by late control angiograms. Until now, one angiogram was performed at only 4 months postoperatively, showing patency of IMA and vein graft to LAD and diagonal branch, respectively. Based on our bad experience with sequential left IMA graft in an unstable patient who had to be bridged to heart transplantation by a ventricular assist device, we no longer perform sequential IMA grafts in unstable patients after failed PTCA. The reperfusion or bailout catheter has been proposed as a temporizing device to reduce myocardial ischemia, restore hemodynamic stability, and in some cases allow performance of an optimal revascularization after failed PTCA [9, 20, 22, 231. In the present study, all patients receiving a reperfusion catheter were stable before operation, except for 2 cases of ventricular fibrillation. Eimergency institution of cardiopulmonary bypass was not required in any of these patients. They never required antiarrhythmics postoperatively. In this small group of patients managed with the reperfusion catheter, we could not confirm a significant reduction in incidence of MI observed by others [20], or demonstrate a significant impact on other parameters of postoperative outcome. Nevertheless, we believe that this catheter may be very helpful in obtaining hemodynamic stability before emergency CABG, an objective that should always be pursued because of its benefit on clinical outcome. Although reports on late follow-up after emergency CABG for failed PTCA are scarce [ l l , 241, studies on late outcome after use of IMA grafts in these situations are lacking. It remains uncertain whether the beneficial impact of the use of IMA grafts on long-term results applies

Ann Thorac Surg 1994;571295-9

also to these emergency bypass procedures after failed PTCA.

References 1. Gruntzig A. Transluminal dilatation of coronary artery stenosis. Lancet 1978;1:263. 2. Holmes DR, Holubkov R, Vlietstra RE, et al. Comparison of complications during percutaneous transluminal coronary angioplasty from 1977 to 1981 and from 1985 to 1986: the National Heart, Lung and Blood Institute percutaneous transluminal coronary angioplasty registry. J Am Coll Cardiol 1988;12:1149-55. 3. Greene MA, Gray LA Jr, Slater AD, Ganzel BL, Mavroudis C. Emergency aortocoronary bypass after failed angioplasty. Ann Thorac Surg 1991;51:19&9. 4. Zapolanski A, Rosenblum J, Myler RK, et al. Emergency coronary artery bypass surgery following failed balloon angioplasty: role of the internal mammary artery graft. J Card Surg 1991;6:439-48. 5. Lytle BW, Loop FD, Cosgrove DM, et al. Long-term (5 to 12 years) serial studies of internal mammary artery and saphenous vein coronary bypass grafts. J Thorac Cardiovasc Surg 1985;89:248-58. 6. Loop FD, Lytle BW, Cosgrove DM, et al. Influence of the internal-mammary-artery graft on 10-year survival and other cardiac events. N Engl J Med 1986;314:1-6. 7. Caes FL, Francois KJ, Primo G, Van Nooten GJ. Heart transplantation after emergency coronary artery bypass for failed angioplasty. Tex Heart Inst 1992;19:300-3. 8. Detre K, Holubkov R, Kelsey S, et al. Percutaneous transluminal coronary angioplasty in 1985-1986 and 1977-1981. The National Heart, Lung and Blood Institute Registry. N Engl J Med 1988;318:265-70. 9. Borkon AM, Failing TL, Piehler JM, Killen DA, Hoskins ML, Reed WA. Risk analysis of operative intervention for failed coronary angioplasty. Ann Thorac Surg 1992;54:8&91. 10. Pelletier LC, Pardini A, Renkin J, David PR, Hebert Y, Bourassa MG. Myocardial revascularization after failure of percutaneous transluminal coronary angioplasty. J Thorac Cardiovasc Surg 1985;90:265-71. 11. Connor AR, Vlietstra RE, Schaff HV, Ilstrup DM, Orszulak TA. Early and late results of coronary artery bypass after failed angioplasty. J Thorac Cardiovasc Surg 1988;96:191-7.

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12. Murphy DA, Craver JM, Jones EL et al. Surgical management of acute myocardial ischemia following percutaneous transluminal coronary angioplasty. J Thorac Cardiovasc Surg 1984;87:332-9. 13. Lazar HL, Haan CK. Determinants of myocardial infarction following emergency coronary artery bypass for failed percutaneous coronary angioplasty. Ann Thorac Surg 1987;M 646-50. 14. Golding LA, Loop FD, Hollman JL et al. Early results of emergency surgery after coronary angioplasty. Circulation 1986;74(Suppl3):26-9. 15. Naunheim KS, Fiore AC, Fagan DC et al. Emergency coronary artery bypass grafting for failed angioplasty: risk factors and outcome. Ann Thorac Surg 1989;47816-23. 16. Parsonnet V, Fisch D, Gielchinsky I et al. Emergency operation after failed angioplasty. J Thorac Cardiovasc Surg 1988; 96198-203. 17. Brahos GJ, Baker NH, Ewy HG, et al. Aortocoronary bypass following unsuccessful PTCA: experience in 100 consecutive patients. Ann Thorac Surg 1985;40:7-11. 18. Jones EL, Murphy DA, Craver JM. Comparison of coronary artery bypass surgery and percutaneous transluminal coronary angioplasty including surgery for failed angioplasty. Am Heart J 1984;107830-5. 19. Mills NL, Bringaze WL. Preparation of the internal mammary artery graft. J Thorac Cardiovasc Surg 1989;98:73-9. 20. Sundram P, Harvey JR, Johnson RG, Schwartz MJ, Baim DS. Benefit of the perfusion catheter for emergency coronary artery grafting after failed percutaneous transluminal coronary angioplasty. Am J Cardiol 1989;63:282-5. 21. Tobe M, Ozaki T, Sakamoto A, et al. Selection of graft materials in case of emergency coronary bypass surgery following failed angioplasty. Kyobu-Geka 1992;45(Suppl): 686-9. 22. Ferguson TB, Hinohara T, Simpson J, Stack RS, Wechsler AS. Catheter reperfusion to allow optimal coronary bypass grafting following failed transluminal coronary angioplasty. Ann Thorac Surg 1986;42:399-405. 23. Kereiakes DJ, Abbottsmith CW, Callard GM, Flege JB. Emergent internal mammary artery grafting following failed percutaneous transluminal coronary angioplasty: Use of transluminal catheter reperfusion. Am Heart J 1987;113:1018-20. 24. Stark KS, Satler LF, Krucoff MW, Rackley CE, Kent KM. Myocardial salvage after failed coronary angioplasty. JACC 1990;15:78-82.

INVITED COMMENTARY This series touting the use of the internal mammary artery as a bypass conduit in emergency cases is impressive in results, although small in number. Caes and Van Nooten are obviously very adept technically, as bypass and aortic cross-clamp times are short, and internal mammary artery takedown requires only 10 minutes or less. The excessively long interval between angioplasty failure and operation can be explained by the system that prevails in the authors’ institution; unfortunately, this time would be unacceptable in many areas, and may contribute to some degree to the rather high incidence of perioperative infarction (44% overall). Use of intraaortic balloon support was essentially nonexistent in this series (1 patient). The hypothesis that the explanation lies with less than ideal interdepartmental communication helps to explain the prolonged transit time to the operating room but does not

justify tolerance of inappropriate logistics detrimental to the patients’ well-being. Although Caes and Van Nooten have shown that the internal mammary artery can be used in emergency cases with acceptable results, one cannot conclude that this represents optimal therapy in every instance. As in many other problematic areas, the ultimate result can be measured only after long-term assessment of left ventricular function. W. Gerald Ruiner, M D

Section of Cardiac Surgery St. Joseph Hospital 2005 Franklin St, Suite 700 Denver, CO 80205