Asian Cardiovasc Thorac Ann 1998;6:195-198
© 1998 Asia Publishing EXchange Pte Ltd
Emergency Coronary Artery Bypass Grafting After Failed Angioplasty
Binali Mavita
, MD,
A Tulga Ulus, MD,
Ülkü Yildiz, MD,
Birol Yamak, MD,
C Levent Birincio
lu, MD,
S Fehmi Katirciolu, MD,
Can Özer, MD,
Ouz Tademir, MD,
Kemal Bayazit, MD
Department of Cardiovascular Surgery and Department of Cardiology Türkiye Yüksek  htisas Hospital Ankara, Turkey
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For reprint information contact: Binali Mavita, MD Department of Cardiovascular Surgery Türkiye Yüksek Ihtisas Hospital Sihhiye, Ankara 06100, Turkey Tel: 90 542 811 7761 Fax: 90 312 466 3202 Email: ulus{at}escortnet.com
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ABSTRACT
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Of 602 patients who underwent percutaneous transluminal coronary angioplasty in a 6-year period, 18 required emergency coronary artery bypass grafting within 12 hours of the procedure. The indications for emergency surgery were acute myocardial infarction in 5 patients, coronary artery dissection in 4, ventricular fibrillation in 3, unstable angina pectoris in 2, total coronary occlusion in 3, and cardiogenic shock in 1 patient. All patients were taken to the operating room in a deteriorating hemodynamic state; 4 received vasodilatating agents and another 4 were treated with vasodilators and inotropic agents, intra-aortic balloon pumping was used in 7, an autoperfusion catheter in 1, and 1 other required external cardiac massage. One patient was operated on in the catheterization laboratory. There was 1 death, giving an operative mortality of 5.6%. The internal thoracic artery was used for coronary artery bypass grafting in 7 patients. There were no deaths during the long-term follow-up.
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INTRODUCTION
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Although percutaneous transluminal coronary angioplasty (PTCA) is successful in most cases, the invasiveness of this technique carries a related risk. The pitfalls include major plaque disruption and coronary artery injury that compromises blood flow with resulting severe ischemia. After PTCA was introduced into clinic practice, it gained widespread acceptance.1 The risk of complications or failure of this technique poses a new challenge to the surgeon, reflected in the necessity of emergency operations after PTCA. This report reviews our experience in patients who underwent PTCA that resulted in the need for emergency surgery because of severe complications following coronary artery dilatation.
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PATIENTS AND METHODS
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PTCA was carried out on 602 patients in the cardiology clinic at Türkiye Yüksek htisas Hospital during a 6-year period. Eighteen of these patients required emergency coronary artery bypass grafting (CABG) because of failure of the PTCA and life-threatening complications. Preoperative findings are listed in Table 1
. The indications for emergency surgery are listed in Table 2. Coronary angiography during PTCA revealed that 5 cases had single-vessel disease. Preoperative angiographic data are shown in Table 3. It can be seen that all 18 of these patients had a severely diseased left anterior descending coronary artery.
Left ventricular wall motion was scored for 7 segments and graded as normal (1 point), hypokinetic (2 points), akinetic (3 points), dyskinetic (4 points), or aneurysmal (5 points). The total score of the 7 segments was used to define ventricular function: normal ventricular function, 7 points; mildly depressed ventricular function, 8 to 14 points; severely depressed ventricular function, 15 points or greater. According to this classification, 3 of the patients had normal ventricular function, 10 had mildly depressed ventricular function, and 5 had severely depressed ventricular function. All were in a state of hemodynamic deterioration prior to surgery.
Eight patients were transferred to the operating room directly from the catheterization laboratory; 4 of these had coronary artery dissection, 3 had total occlusion of a coronary artery, and 1 was in cardiogenic shock. All 18 patients were operated on within 12 hours of the angioplasty procedure. Five patients with acute myocardial infarction had prolonged angina, ST-segment elevation unresponsive to vasodilating agents, and ventricular tachycardia. In 2 patients with unstable angina pectoris, PTCA had to be ceased because of severe chest pain and rhythm disturbances; they were transferred to the intensive care unit for close observation. Even though the rhythm disorder was relieved by antiarrhythmic drugs, the chest pain persisted with ischemic changes seen in the electrocardiogram.
All 18 patients required some measure of ventricular support postoperatively. Four patients were transferred to the operating room while receiving vasodilatating agents and another 4 were given vasodilatating and inotropic agents, 7 patients needed intra-aortic balloon pump support, 1 had an autoperfusion catheter inserted, and 1 required external cardiac massage. The other patient who had acute coronary occlusion, underwent surgery in the catheterization laboratory because of extreme hemodynamic instability that did not permit transfer to the operating room.
The operations were performed with standard cannulation and a membrane oxygenator under moderate systemic hypothermia (20°C to 30°C). Cold potassium cardioplegia (1 L) was used for myocardial protection with infusions of cold blood cardioplegia at 20-minute intervals. Ice-cold saline was used for topical cooling. Infusions of cardioplegic solution were repeated after each distal anastomosis to maintain the myocardial temperature at below 18°C. The internal thoracic artery was used as a coronary artery bypass graft to the anterior descending artery in 7 patients who were hemodynamically stable and the others received saphenous vein grafts.
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RESULTS
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There was one hospital death of a patient who had acute myocardial infarction and underwent surgery 10 hours after a failed elective PTCA. The overall mortality was 5.6%. Postoperative morbidity was observed in 11 patients and comprised low cardiac output managed with intra-aortic balloon pumping in 4, arrhythmias in 2, perioperative myocardial infarction in 1, excessive bleeding in 2, a costal fracture in 1, and ventricular fibrillation in 1. One patient was reexplored due to excessive bleeding in the early postoperative hours but no surgical cause was found.
Electrocardiograms showed signs of impending myocardial infarction in 5 patients preoperatively but returned to normal postoperatively in all but 1, with no significant increases in creatine kinase-MB isoenzyme, which implies that myocardial necrosis had been prevented. Long-term follow-up ranging from 12 to 62 months (mean, 36 months) was achieved in the 17 patients discharged from the hospital. There were no deaths during follow-up.
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DISCUSSION
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PTCA can be performed successfully in the majority of patients but some may develop restenosis or recurrent symptoms. CABG in these patients is no different in terms of indications and risk from those who have not undergone PTCA. In some cases, PTCA may result in acute aggravation of myocardial ischemia. It is possible that better technical design might decrease the failure and complication rates. Certain complications of PTCA require emergency surgical interventions to limit the injury. The incidence of complications was found to be 10% in a multicenter study.1 In our series, emergency CABG was necessary in 3% of cases. Two important factors that correlate directly with the occurrence of complications are the extent of coronary artery disease and the absence of collateral circulation to the diseased coronary artery.1,2
The majority of our patients (13/18) had multiple-vessel disease and mildly or severely depressed ventricular function (15/18). The mortality was 5.6% and the morbidity was 61% (11/18). The perioperative mortality in a recent series reported by Bartram and colleagues3 was 8.3%. The functional class indicating the hemodynamic stability of the ventricles is a key factor in postoperative morbidity. However, the successful results after emergency CABG suggest that immediate surgery should be performed in all such patients.
Circulatory support with an intra-aortic balloon pump has proved to be a useful adjunct that permits stabilization of patients preoperatively.4 In 7 of our patients, intra-aortic balloon pumping effectively reduced the signs of ischemia. It has also been found to decrease ventricular afterload, wall tension, myocardial oxygen consumption, and the area of injury, while improving coronary blood flow.5 One of our patients with impending myocardial infarction was treated with nitroglycerine and underwent surgery 10 hours after PTCA. After the operation, this patient had evidence of definite infarction, failed to respond to intra-aortic balloon pumping, and died as a result of low cardiac output. We consider that the delay between coronary occlusion and revascularization must be kept to a minimum to limit the extent of myocardial ischemia and necrosis.
In one of the patients with unstable angina, myocardial infarction occurred perioperatively as evidenced by the appearance of new Q waves or loss of R waves in at least two electrocardiographic leads. An intra-aortic balloon pump was used preoperatively and this patient came off cardiopulmonary bypass without any problem. The use of this technique preoperatively and postoperatively combined with revascularization of the ischemic myocardium within a period of 4 hours can salvage ischemic myocardium. In one patient, an autoperfusion catheter was used to carry the blood distal to the occlusion. During surgery it can provide cardioplegic solution to the ischemic myocardium.6
In our hospital, a surgeon is alerted at the first sign of arterial injury. If myocardial ischemia responds to medical intervention, the patient is observed until all of the symptoms have resolved. Hemodynamically unstable patients receive balloon pump support to minimize ischemic injury. If the patient is extremely unstable, the catheterization laboratory must be transformed into an operating theater to reduce the delay between arterial injury and surgery.
The most important factor that we observed to be related to morbidity was an unstable hemodynamic condition. After failed PTCA, if the hemodynamic condition is relatively stable, surgical treatment can be postponed. Although emergency revascularization was performed in patients in whom dilatation could not be achieved, some patients who required emergency surgery had initially successful dilatation with angiographic improvement followed by abrupt reclosure of the dilated vessel. Our experience gives further support to the use of mechanical assist devices in patients with depressed ventricular function.7–9 We concluded that after PTCA failure, emergency CABG can reduce the incidence of acute myocardial infarction and death.
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REFERENCES
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ABSTRACT
INTRODUCTION
