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J Thorac Cardiovasc Surg 1995;110:214-223
© 1995 Mosby, Inc.
SURGERY FOR ACQUIRED HEART DISEASE |
Loma Linda, Calif.
From the Division of Cardiothoracic Surgery, Department of Surgery, Loma Linda University Medical Center, Loma Linda, Calif.
Address for reprints: Nan Wang, MD, Assistant Professor of Surgery, Division of Cardiothoracic Surgery, Loma Linda University Medical Center, Department of Surgery, 11234 Anderson St., Loma Linda, CA 92354.
Abstract
In recent years, there has been a nationwide trend toward performing percutaneous transluminal coronary angioplasty in patients with multivessel coronary artery disease. The clinical course of 57 consecutive patients who required emergency first-time coronary artery bypass grafting operations were reviewed to assess for difference in outcome between the 28 patients (49%) with single-vessel disease and the 29 patients (51%) with multivessel disease. The two groups were similar in preoperative characteristics except for a higher proportion of chronic obstructive pulmonary disease in the patients with multivessel disease (p = 0.03). Twice as many patients with multivessel disease were in shock (single-vessel disease = 4 [14%], multivessel disease = 8 [28%], p = not significant) en route to the operating room and significantly more patients with multivessel disease required on-going cardiopulmonary resuscitation (single-vessel disease = 0 [0%], multivessel disease = 5 [17%], p = 0.03). Significantly more coronary artery bypass grafts were placed in the patients with multivessel disease (single-vessel disease = 1.5±0.6, multivessel disease = 2.9±0.7, p < 0.01), which required longer aortic clamping time (p = 0.02) and cardiopulmonary bypass time (p < 0.01). There were seven postoperative deaths; all but one occurred in patients with multivessel disease (single-vessel disease = 1 [4%], multivessel disease = 6 [21%], p = 0.05). According to multivariate analysis, incremental risk factors of mortality were preoperative shock (p < 0.01), urgent or emergency percutaneous transluminal coronary angioplasty (p = 0.06), and multivessel disease (p = 0.12). Despite a similar incidence of myocardial infarction (single-vessel disease = 8 [29%], multivessel disease = 12 [41%], p = not significant), patients with multivessel disease had a higher incidence of cardiac morbidity (single-vessel disease = 4 [14%], multivessel disease = 11 [38%], p = 0.04) and noncardiac morbidity (single-vessel disease = 4 [14%], multivessel disease = 12 [41%], p = 0.02). By multivariate analysis, incremental risk factors of morbidity were preoperative shock (p < 0.01), multivessel disease (p = 0.02), and ejection fraction < 50% (p = 0.07). In the subset of patients with multivessel disease, preoperative shock, ejection fraction < 50, and an age of 60 years or greater were associated with higher morbidity and mortality. In conclusion, the risk of percutaneous transluminal coronary angioplasty failure is considerably higher in patients with multivessel disease. In certain subsets of patients with multivessel disease, coronary artery bypass grafting would be a safer procedure when compared with percutaneous transluminal coronary angioplasty for initial myocardial revascularization. (J THORACCARDIOVASCSURG1995;110:214-23)
In the past decade, the number of percutaneous transluminal angioplasty (PTCA) procedures performed has escalated dramatically. An estimated 300,000 PTCA procedures were done in 1990.
1 The broadening of the clinical indications for PTCA is the most likely cause for such a trend. A notable change in the PTCA patient profile is the substantial increase in the proportion of patients with multives sel coronary artery disease (MVD). 1, 2 According to the most recent National Heart, Lung, and Blood Institute PTCA Registry, over 50% of the patients with PTCA had MVD. 2 Bell and associates 3 reported even a higher percentage of their patients (83%) as having MVD. The overall risk of PTCA has already been affected by such a change in PTCA practice. The patients with MVD were found to have a significantly higher mortality rate (one vessel = 0.2% versus two vessels = 0.9% versus three vessels = 2.8%). 2 Ellis and associates 4 also reported an increase in in-hospital cardiac deaths in the patients with MVD in the setting of acute vessel closure from PTCA. Do these findings, in fact, also affect the risk of emergency coronary artery bypass grafting (CABG) in the event of PTCA failure?
Antecdotally, we have noted an alarming trend of more patients arriving to the operating room in moribund condition after PTCA failures. We have also observed that these patients were more likely to have MVD. In their moribund condition, these patients had fared poorly from emergency CABG despite having relatively low preoperative risks before PTCA. This study is therefore undertaken to determine whether MVD indeed increases the risk of emergency CABG after PTCA failure and whether certain MVD patient subsets have a prohibitively high risk of PTCA failure, thus making them better CABG candidates.
PATIENTS AND METHODS
Patient population
Between June 1, 1988, and January 31, 1994, a total of 2307 PTCA procedures were performed in 1866 patients at Loma Linda University Medical Center. From this registry, 60 cases (2.6% of the PTCA cases) were identified as PTCA failures requiring emergency CABG operations because of acute vessel closure, thrombosis, or dissection. These cases were true emergencies in that all patients had clinical evidence of on-going ischemia such as angina or electrocardiogram changes. The majority of the patients (93%) were transferred from the PTCA suite to the operating room for immediate CABG. Four patients had delayed onset of ischemia and required emergency CABG within 24 hours of PTCA.
The perioperative course of these 60 patients were reviewed. Three patients were excluded from the study on the basis of having had prior CABG (two patients) and untreated severe mitral valve disease (one patient). Thus, this study consisted of the remaining 57 patients who had coronary artery disease as their only cardiac pathologic condition and CABG as their first operation. These patients were divided into two groups: 28 patients (49%) with single-vessel disease (SVD), and 29 patients (51%) with MVD. This proportion resembled the proportion of the entire population in the PTCA Registry (SVD = 48%, MVD = 52%).
Operative strategy
All PTCA procedures had prearranged surgical backup, and the level of support was determined according to the recommendation of the American College of Cardiology and American Heart Association. 1 Essentially all patients had level 2 support, and none of these patients met the criteria for level 3 support. In the event of acute vessel closure, an attempt was made by the cardiologist to reverse acute myocardial ischemia by inserting a perfusion catheter across the site of occlusion. Stenting of the coronary artery was attempted in two patients. Only recently were intraaortic balloon pumps (IABP) inserted on a regular basis in the patients with unstable conditions.
On arrival to the operating room, all patients except for three were supported with cardiopulmonary bypass via median sternotomy as soon as possible. In three patients, single-vessel CABGs were performed without cardiopulmonary bypass. In patients with a suitable left anterior descending target, the left internal thoracic artery was taken down as a conduit in the patients with relatively stable conditions. Frequently, dissection of the left internal thoracic artery was done after commencement of cardiopulmonary bypass.
The method of myocardial protection varied according to the surgeon's preference There were primarily three modes of myocardial protection: cold, intermittent, antegrade or retrograde, oxygenated crystalloid cardioplegic solution; cold, intermittent, retrograde, blood cardioplegic solution; or warm, continuous, retrograde, blood cardioplegic solution. Inotropes were used at the end of the operation only when deemed necessary. In patients with severely compromised postoperative hemodynamics, IABP or ventricular assist devices (centrifugal pumps) were inserted and used.
Outcome analysis
The postoperative mortality and morbidity of the two groups of patients were analyzed and compared. Mortality was defined as any in-hospital death or death within 30 days of CABG. Morbidity was defined according to the major complication types in the National Cardiac Surgery Database as proposed by the Society of Thoracic Surgeons. Any complication was further categorized into either cardiac or noncardiac complication. Myocardial infarction was also examined as an end-point and was defined as having any new finding on serial electrocardiogram or postoperative echocardiography subsequent to PTCA failure.
Univariate comparisons between the two groups of patients were performed with the use of the Fisher exact or the 
2 analysis for discrete variables and unpaired Student's t test for continuous data. Certain continuous data were converted into discrete proportions by predetermined cut points, and these discrete proportions were retested with 2 analysis. Further analysis of morbidity and mortality was carried out with the use of a multivariate model. All preoperative or operative variables (Appendix A) found to be of significance (p < 0.05) or marginal significance (p < 0.10) with the univariate method were entered into a logistic regression analysis for morbidity and mortality. This analysis was performed to assess the independent contributions of the multiple variables to the development of postoperative morbidity and mortality. All calculations were performed with the SPSS, version 4.0.2 statistical program (Statistical Package for the Social Sciences, Chicago, Ill.) for the Macintosh computer (Apple Computer, Cupertino, Calif.).
RESULTS
Patient profile
The preoperative characteristics of the two groups of patients are shown on Table I. Both groups consisted of patients with a mean age close to 60 years with essentially normal ejection fractions. Although not significant, diabetes mellitus was more prevalent in the MVD group, and the female gender was more prevalent in the SVD group. The two groups were comparable except for a significantly increased proportion of chronic obstructive pulmonary disease in the MVD group. However, by univariate analysis, chronic obstructive pulmonary disease did not significantly influence the postoperative outcome.
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Table II) PTCA of more than one coronary artery distribution was performed in 28% of the patients with MVD. Additional devices such as stents, arthrectomy catheters, or laser devices were applied more frequently to the SVD group.
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Significantly more bypass grafts were used in the patients with MVD (Table III), thus cardiopulmonary bypass time and aortic clamping time were necessarily longer Cardioplegia was not used in five patients. Three of these patients had a single-vessel coronary bypass performed without cardiopulmonary bypass; and the other two patients were revascularized while supported with cardiopulmonary bypass without clamping the aorta. The majority of the patients (91%) had one of three modes of myocardial protection. Although a difference in the method of myocardial protection was apparent in the patients with SVD versus those with MVD, the mode of myocardial protection did not contribute significantly to the postoperative outcome by univariate analysis.
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Table I), the overall mortality in this series was 11.7%, which was considerably higher than the mortality rate of primary CABG operations performed during the same period of time (2% to 3%) at the same institution. However, all except for one death occurred in patients with MVD. This difference in mortality was also significant (MVD = 21%, SVD = 4%, p = 0.05) (Table IV). Of the six deaths in the patients with MVD, one patient had a prolonged PTCA attempt of both the right coronary artery and the left anterior descending artery. After successful CABG, he had sudden cardiac arrest and could not be resuscitated. Autopsy showed a large myocardial infarction with patent grafts. The remaining five patients were brought to the operating room in shock; three had on-going cardiopulmonary resuscitation. An IABP was inserted in one patient before the operation in the PTCA suite, but it was ineffective because the patient was in full arrest. Four of these five patients continued in a low cardiac output state after the operation and died shortly thereafter. The final patient died of multisystem organ failure approximately 1 week after the CABG operation. There was only one death in the SVD patient group. This patient had a prolonged attempt at angioplasty of a complex right coronary artery lesion. She was deemed a poor surgical candidate because of her age and accompanying renal failure from polycystic kidney disease. Prolonged ischemia accompanied the multiple attempts at opening the acutely occluded right coronary artery. She died of sepsis and multiple organ system failure a week after the operation.
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According to univariate analysis (Table V), the increase in risk of mortality was significant in these patients: age > 60 years (p = 004), preoperative shock (p < 0.01), MVD (p = 0.05); the increase in risk was mildly significant in these patients: ejection fraction < 50% (p = 0.08), urgent or emergency PTCA (p = 0.09). According to multivariate analysis (Table VI), the independent predictors of mortality were as follows: preoperative shock (p < 0.01), urgent or emergency PTCA (p = 0.06), MVD (p = 0.12). Because of the small number of outcome events (deaths), MVD was only marginally significant as an independent predictor of mortality.
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60 years (p = 0.08).
Morbidity
As shown in Table IV, the incidences of postoperative cardiac morbidity (SVD = 14%, MVD = 38%, p = 0.04) and noncardiac morbidity (SVD = 14%, MVD = 41%, p = 0.02) were significantly higher in the patients with MVD. In fact, only 4 of the 28 patients with SVD had any morbidity at all. In the patients with MVD, almost one third had evidence of low cardiac output in the postoperative period, and almost a quarter had cardiac arrest either from arrhythmias or ischemia after the operation.
Centrifugal pumps were used as left ventricular assist devices in four patients. Only one patient survived, and this patient had SVD. The rates of postoperative myocardial infarction were similar in both groups (SVD = 29%, MVD = 41%), but the complications of perioperative myocardial infarction such as low cardiac output or cardiac arrest events were greater in the patients with MVD, suggesting more profound myocardial damage in the patients with MVD. Accompanying the increase in morbidity in the patients with MVD, the length of hospital stay was also increased (SVD = 7.0 ± 3.0 days, MVD = 10.3 ± 5.4 days, p = 0.07).
According to multivariate analysis (Table VI), the independent predictors of morbidity were as follows: preoperative shock (p < 001), MVD (p = 0.02), and ejection fraction < 50% (p = 0.07). MVD was therefore a significant independent risk factor of morbidity.
As expected, preoperative shock increased the cardiac and noncardiac morbidity in both SVD and MVD patient subsets. No other predictors of morbidity were found in the SVD patient subset. But in the MVD patient subset, other risk factors were age 60 years for cardiac morbidity (p = 0.03) and an ejection fraction < 50 for noncardiac morbidity (p = 0.02).
DISCUSSION
Over the past decade, the number of PTCA procedures performed in the United States has increased ten-fold. 5 As cardiologists have gained greater PTCA experience, the clinical indications for PTCA have broadened considerably. When PTCA was introduced in 1977, the procedure was designed to treat patients with SVD with discrete, proximal, noncalcified, subtotally occlusive lesions. 6 By 1980, a substantial proportion (40%) of patients treated with PTCA had MVD. 7 Currently, more patients with MVD (50% to 60%) 1, 2 than patients with SVD undergo PTCA daily. As PTCA emerges to become the preferred method of achieving myocardial revascularization in patients with MVD, 3, 8, 9 there is mounting evidence that the overall outcomeis not as favorable 2, 10 and that the potential for serious complications is greater. 4, 11 Furthermore, O'Keefe and associates 9 found that a considerable higher proportion of patients with MVD (16%) required early CABG operations after PTCA. Similarly, in the Heart, Lung, and Blood Institute PTCA Registry, CABG operations were more frequently required (6% to 8%) in the patients with MVD; approximately half of these operations were done on an urgent or emergency basis.
Our experience over the past 6 years reflected a similar trend MVD was present in over 50% of our patients undergoing PTCA. Although PTCA failures requiring emergency CABG had occurred just as often in the SVD as in the MVD patient subsets, we found the operative complications to be significantly greater in the patients with MVD. Only one of the seven postoperative deaths occurred in a patient with SVD. The overall mortality in this series was 11.7%, which is comparable with that of other reports 12-18 ; but the mortality in patients with MVD was considerably higher (SVD = 3.6%, MVD = 20.5%, p = 0.05). Our data corroborated those of other studies 15, 18, 19 which also showed an increased risk of emergency CABG for PTCA failure when MVD was present.
Several factors contributed to the relatively high mortality in the patients with MVD in this series. As several investigators had found, 12, 13, 17 operative mortality for PTCA failures had not changed significantly over the past decade, despite advances in surgical technique and myocardial protection. Because of the change in patient profile, Boylan and associates 13 had found the operative mortality to beeven higher. Talley 19 and Connor 20 and their associates reported exceptionally low mortality figures, but the patient populations in their series were different. They had included the patients with more stable conditions who had essentially elective CABG operations within several days of their PTCA failures. In this series, all but four patients were transferred directly to the operating room from the PTCA suite because of unstable ischemic or hemodynamic findings. The remaining four patients also required true emergency CABG operations for acute onset of ischemia within 24 hours of PTCA failures. Less urgent CABG candidates were not included in the study. Furthermore, a significant proportion of patients (9 of 23, 31.0%) had three-vessel disease in this series. But probably the most important reason for the high mortality in the patients with MVD was the presence of severe hemodynamic instability in over one third of these patients after PTCA failure.
Cardiogenic shock after PTCA failure was a definite incremental risk factor for postoperative mortality in many large series. 13, 14, 16, 18 By multivariate analysis, cardiogenic shock was the single most significant (p < 0.01) independent risk factor for mortality in the present study. However, the impact of preoperative hemodynamic instability on mortality was only evident in the patients with MVD. The overall incidence of cardiogenic shock immediately after PTCA failure was 20% (SVD = 14.3%, MVD = 27.6%). But none of the four patients with SVD with preoperative cardiogenic shock required cardiopulmonary resuscitation, and all ultimately survived. In contrast, of the eight patients with MVD with preoperative cardiogenic shock, five (68%) required preoperative cardiopulmonary resuscitation and half of these patients eventually died. The patients with SVD probably had more myocardial reserve which would allow for a safer transition from the PTCA suite to the operating room even in the presence of profound hemodynamic instability. The patients with MVD would more likely have a greater amount of myocardium at risk in the event of acute vessel closure. It may therefore be important that an objective clinical parameter such as the myocardial jeopardy index, 21, 22 which has been shown to correlate with postoperative outcome, 4, 21-23 be used, particularly in the patients with MVD, to better stratify their PTCA risk. Patients with MVD and high myocardial jeopardy index are probably at a greater risk of cardiogenic shock in the event of PTCA failure. The consequence of cardiogenic shock in such patients can be catastrophic, as is shown in the present study.
In addition to preoperative shock, other significant or marginally significant risk factors for postoperative mortality in the patients with MVD were an ejection fraction < 50% (p = 0.05) and age 
60 years or older (p = 0.08). These findings are compatible with findings in other series. 16, 24 Older patients and patients with lower ejection fractions have less cardiac and physiologic reserve. They are less likely to tolerate an acute vessel closure complication. Elderly patients with MVD and even a mildly impaired left ventricular function are probably better served by CABG instead of PTCA.
According to multivariable analysis, operative morbidity was also significantly higher in the patients with MVD. Such increases in morbidity in the patients with MVD were also observed by other investigators. 15, 19, 25 Greene and associates 15 reported substantial differences between patients with SVD and patients with MVD with regard to inotropic support for low cardiac output (MVD = 75%, SVD = 57%) and IABP requirement (MVD = 25%, SVD = 5%). The present series showed a similar trend. The overall incidence of low cardiac output requiring prolonged inotropic support was 21%, considerably lower than 24% to 68% reported in other studies 14, 15, 24 but was higher in the patients with MVD (SVD = 11%, MVD = 31%, p = 0.06). Although not significant, the use of IABP was twice as high in the patients with MVD (SVD = 7%, MVD = 17%).
The more complicated course of patients with MVD may be inferred by comparing the length of hospital stay (SVD = 71 ± 3.0 days, MVD = 10.3 ± 5.4 days, p = 0.07). A similar difference was also noted by Greene and associates 15 (SVD = 10.5 ± 2.9 days, MVD = 15.0 ± 9.9 days, p < 0.05). Our overall average length of stay compared favorably with the results of other series which ranged between 12 to 16 days. 12, 14, 15
On the basis of our findings, we suggest that patients with MVD are at a higher risk for postoperative morbidity and mortality in the event of PTCA failure. Because more than half of the patients undergoing PTCA each day have MVD, it is unlikely that cardiologists will alter this practice pattern unless the long-term result of CABG is found to be far superior to that of PTCA. However, our series suggests that greater caution should be exercised and selection of patients with MVD for PTCA should be more specific. The risk of PTCA appears particularly high in these patients with MVD: (1) age greater than 60 years, (2) ejection fraction less than 50%, and (3) estimate of a large amount of myocardium at risk in the event of acute vessel closure. The patient with MVD with one or more of these characteristics should receive formal surgical consultation so that he or she may make an informed choice. In patients who still opt for PTCA, the level of surgical support should be heightened. In the event of acute vessel closure, every possible measure, particularly in the liberal use of IABP 26 or even percutaneous cardiopulmonary bypass, must be taken in the PTCA suite to attempt to restore satisfactory hemodynamic status and reverse ischemia as soon as possible. Then expedient transfer of the patient to the operating room for immediate revascularization must be carried out.
CONCLUSION
According to the results of emergency revascularization for PTCA failure in 57 patients, patients with MVD are at significantly higher risk for morbidity and mortality from a failed PTCA. Patients with MVD over 60 years of age with a large proportional amount of myocardium at risk may be best served by primary surgical revascularization rather than PTCA.
Appendix: DISCUSSION
Dr. Frederick L. Grover (Denver, Colo.).
Dr. Wang has emphasized the increased risk of patients having emergency CABG after a failed PTCA in a MVD subgroup as compared with those patients with SVD. This type of analysis is obviously important because the knowledge of the risk of a failed PTCA requiring surgical intervention must be used in the judgement of the management of these patients in whom angioplasty is being considered as a therapeutic option. This information is not only necessary for the physicians who are recommending the most appropriate treatment but also for the patients so they are truly signing an informed consent. Dr. Wang has shown a significantly higher operative mortality for the MVD group as compared with the SVD group, but these numbers are small. Because of the small numbers they must be interpreted with caution. Patient risk factors other than the number of diseased vessels were similar except for a greater incidence of shock and cardiopulmonary resuscitation and the decreased ejection fraction in the MVD group.
To determine whether others obtain similar outcomes, I reviewed the national Veterans Affairs cardiac surgical database and reviewed the data from the New York State database courtesy of Dr Ed Hannon and the Society of Thoracic Surgeons database courtesy of Drs. Dick Clark, Fred Edwards, and Mark Schwartz.
In the Veterans Affairs database, 11,474 coronary bypass procedures were performed from 1991 through 1993. There were 504 single CABGs, 45 of which were emergency procedures done within 12 hours of angioplasty with an operative mortality of 11.1%. The risk factors other than the urgent nature of the procedure and the angioplasty failure were not great, as shown by an estimated operative mortality of only 4.9%. Seventy-nine of 10,639 patients with MVD who underwent emergency CABG had an angioplasty procedure within 12 hours of the operation with an operative mortality of 16.9%—greater than but not statistically significant compared with the SVD group mainly because the mortality was also high for patients with SVD. This group of patients tended to be at higher risk, as shown by an estimated operative mortality of 11.1%. An IABP was placed before the operation in 49.4% of the MVD group as compared with 27% of the SVD group, and 14% of the patients with MVD had redo procedures compared with only 2.2% of those with SVD.
The New York State database was reviewed for 1993 and showed that 162 patients with SVD had emergency coronary bypass on the same admission as PTCA with two deaths (12%), 106 patients with two-vessel disease with four deaths (3.7%), and 45 patients with three-vessel disease with five deaths (11.1%).
The Society of Thoracic Surgeons database showed that from 1991 to 1993, 3900 patients underwent emergency CABG after PTCA with a mortality rate of 36% for the 1289 patients with SVD as compared with 6.5% for the 2629 patients with MVD. This was significant.
In conclusion, from review of these databases, although there is some variation in how the data are collected in terms of the time from failed PTCA to the operation among the databases, all of them show a substantial risk for patients with MVD undergoing emergency coronary bypass after PTCA, and in the Veterans Affairs database this also occurs in the SVD group. The authors are therefore to be congratulated on bringing this important finding to our attention.
I have a couple of questions that I would like you to address if possible. You have shown that age, shock, and decreased ejection fraction are univariate predictors of poor outcome in these patients in addition to MVD. Was there any attempt to stratify or analyze the data according to the number of vessels angioplastied. Did you investigate not only whether it was a left anterior descending coronary artery or a right coronary artery but also the location within the coronary artery (i.e., proximal coronary), and the complexity of the lesion in terms of the likelihood of this angioplasty failing and resulting in a bad surgical outcome?
Dr. Wang.
The data were collected from the PTCA registry for the most part, and some of the data were collected in a retrospective fashion through patient charts. The number of vessels angioplastied and the type of vessel (i.e., left anterior descending versus right coronary artery) were not significant factors. Location of the lesion (i.e., proximal versus distal) was one particular issue that we tried to sort out, but unfortunately those data were not complete. There were, however, certainly more patients with multiple angioplasties in the MVD group.
Dr. Grover.
What was your use or your cardiologist's use of IABP in the cardiac catheterization laboratory and would more vigorous use of that entity perhaps result in a better surgical outcome? Thank you.
Dr. Wang.
I think you brought up an important point. Our cardiologists until recently were not as enthusiastic in using the IABP in a timely fashion. I think that contributed to some of the patients coming to the operating room in a basically moribund type of condition. This pattern, however, has changed, and IABP is being used much more readily.
Dr. Walter Dembitsky (San Diego, Calif.).
In San Diego, we have gone one step further. We have actually trained nurses and cardiologists to be able to use a portable bypass circuit. When there is a problem with hemodynamic instability in the catheterization laboratory, patients are supported with percutaneous bypass and are stabilized so that shock never really develops. Then, an attempt is made to open vessels in the catheterization laboratory. If the vessels can be opened and the patient is still unable to sustain his own circulation, we support him for several days more in the intensive care unit and then wean him. That has worked very well. If patients do require surgical treatment for unopened vessels, we simply transfer them to the operating room while supported with the bypass machine and then perform the operation on that device by attaching a cardiotomy to it. That does represent a slightly different strategy, and we found it to be successful. I noticed that you did have one patient supported with percutaneous bypass. Are you beginning to develop that kind of a program?
Dr. Wang.
We do have percutaneous bypass available; however, that particular strategy has been reserved for patients who are deemed poor surgical candidates to begin with. In this particular series, these patients in retrospect were fairly good surgical candidates. The reason some were in such a severely hemodynamically compromised state was because there was a large amount of myocardium in jeopardy in the event of vessel closure, and I think this particular subset of patients perhaps should be treated differently. We have used percutaneous cardiopulmonary bypass in one patient who was in complete arrest, and the balloon pump was not able to establish any kind of support. This patient did not survive.
Dr. Dembitsky.
Actually I think that when these patients are dying, the balloon pump is futile. You probably agree with that too.
Dr. Wang.
Yes, I agree.
Dr. Ahmed El Gamel (Manchester, United Kingdom).
There are two queries in my mind. We have analyzed our data for 50 cases done as emergencies after failed angioplasties, and we found that the time from diagnosis of failed angioplasty to the time that the patient underwent operation is an important risk factor, and the shorter this time period the better the results. I wonder if you have found the same thing.
Also, we have concluded that the use of retrograde cardioplegia is of paramount importance in this group of patients, probably antegrade perfusion would not be ideal. Has that been a risk factor with your group?
Dr. Wang.
With respect to the second question, we have analyzed the mode of cardioplegia to see whether that adversely affected the postoperative outcome. I think because of the small numbers involved we were not able to detect a particular difference in outcome.
Dr. El Gamel.
Have you analyzed the anatomic site (i.e. left anterior descending versus right coronary artery) in the outcome of mortality? We think that probably left anterior descending SVD is more dangerous angioplasty failure than right coronary artery disease.
Dr. Wang.
Yes, we have. We looked at the culprit vessels involved, and the interesting finding was that the circumflex artery was the culprit vessel in only one patient. The other patients either had left anterior descending or the right coronary artery as the culprit vessel. The incidence of the left anterior descending coronary artery being the culprit vessel was twice as high as that of the right coronary artery; however, when we looked in a univariate fashion to see if that is predictive of subsequent outcome, we could not find a difference.
Just to answer your first question, we have not actually looked at the amount of ischemic time involved, and I think that is part of the weakness of this study in that we had to rely on PTCA registry information and that was again not available.
Dr. El Gamel.
A last point: How many of the patients had arterial conduits because we found this unsatisfactory in this day and age that you get pressed to perform operations in patients who are seriously ill with veins that are all unusable with no suitable arterial conduit. We think that contributes to the long-term results, and we should alert the cardiologists of the importance of checking on the presence of conduit before attempting something like multivessel PTCA. Is that something you have noticed as well?
Dr. Wang.
We have always tried to use the internal thoracic artery for the left anterior descending target if possible. We routinely take the internal thoracic artery down after we have established cardiopulmonary bypass in these patients. This was possible in about one third of the patients. The other two thirds were either in the elderly age group or were just not stable enough for such an approach. But I do agree with you that these were patients in whom the internal thoracic artery was not be used because of the emergency situation.
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Footnotes
Read at the Twentieth Annual Meeting of The Western Thoracic Surgical Association, Olympic Valley, Calif., June 22-25, 1994. 
References
This article has been cited by other articles:
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  L. D. Hillis, P. K. Smith, J. L. Anderson, J. A. Bittl, C. R. Bridges, J. G. Byrne, J. E. Cigarroa, V. J. DiSesa, L. F. Hiratzka, A. M. Hutter Jr, et al. 2011 ACCF/AHA Guideline for Coronary Artery Bypass Graft Surgery: A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines Developed in Collaboration With the American Association for Thoracic Surgery, Society of Cardiovascular Anesthesiologists, and Society of Thoracic Surgeons J. Am. Coll. Cardiol., December 6, 2011; 58(24): e123 - e210. [Full Text] [PDF]
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 Writing Committee Members, L. D. Hillis, P. K. Smith, J. L. Anderson, J. A. Bittl, C. R. Bridges, J. G. Byrne, J. E. Cigarroa, V. J. DiSesa, L. F. Hiratzka, et al. 2011 ACCF/AHA Guideline for Coronary Artery Bypass Graft Surgery: A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines Circulation, December 6, 2011; 124(23): e652 - e735. [Full Text] [PDF]
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 H. L. Lazar, A. K. Jacobs, G. S. Aldea, O. M. Shapira, D. Lancaster, and R. J. Shemin Factors Influencing Mortality After Emergency Coronary Artery Bypass Grafting for Failed Percutaneous Transluminal Coronary Angioplasty Ann. Thorac. Surg., December 1, 1997; 64(6): 1747 - 1752. [Abstract] [Full Text]
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