Coronary Endarterectomy and Bypass Grafting without Cardiopulmonary Bypass

INTRODUCTION

Coronary endarterectomy was one of the first surgical procedures used for ischemic heart disease,^1,2 although technical limitations led to discouraging results.² When combined with aortocoronary bypass and extracorporeal circulation, long-term bypass patency was 64% versus over 90% for bypasses in vessels without endarterectomy.³

Coronary artery bypass grafting without cardiopulmonary bypass was first described by Kolessov⁴ and is now a common procedure at most cardiac hospitals, as it has several advantages.⁵

With the advent of percutaneous transluminal coronary angioplasty, the patients now referred for surgery present diffuse, complex lesions⁶ which, along with the condition of the vessel wall at the time of the arteriotomy,⁷ influence the surgical outcome. Therefore, coronary endarterectomy is an option that can be used in combination with anastomosis of aortocoronary bypasses.⁸ We present our experience with simultaneous off-pump coronary artery bypass grafting and endarterectomy.

PATIENTS AND METHODS

Patients who underwent simultaneous off-pump coronary artery bypass grafting and endarterectomy between 1 March 1997 and 28 February 2002 were prospectively included in the study.

Off-pump coronary artery bypass grafting was indicated in patients with more than 70% obstruction and adequate distal anatomy, in whom manipulation of the myocardium did not cause hemodynamic alterations or serious arrhythmias refractory to treatment.

After standard preoperative preparation and immobilization of the myocardial segment selected, arteriotomy was performed. When plaque was found, we evaluated its fragility, thickness, patency, apparent extension, and adherence to the endothelium of the coronary vessel.

If the vessel was not appropriate for anastomosis, we performed endarterectomy by everting and dissecting the plaque from the arterial wall, applying gentle traction and countertraction from the ends of the arteriotomy, then withdrawing the entire plaque from the proximal end (Figure 1). We checked that the entire plaque had been removed by verifying that the tapered end of the plaque had been withdrawn, and confirming proximal and distal blood flow. The same procedure was used in all cases and was followed by standard revascularization.

Fig. 1. Diagram of the procedure. Atheromatous plaque is visualized through the arteriotomy of the left anterior descending artery and excised.

We did not perform endarterectomy in vessels with a diameter under 2 mm, coronary dilation, or plaque in vessels that fed nonviable myocardium.

We investigated arrhythmia, use of inotropic agents, CK-MB levels, other postoperative complications or mortality, plus stress tests and New York Heart Association (NYHA) functional class in the follow-up, considering perioperative infarction to have occurred when the following appeared: Q-waves not visualized in the preoperative electrocardiogram, electrocardiographic changes suggestive of lesion persisting for more than seven days, echocardiographic abnormalities in segmental contractility, as well as CK levels above 400 U/L or CK-MB of 40 U/L.^9,10

RESULTS

During the study period, nine endarterectomies were performed in eight patients (6.2% of off-pump bypass grafts). Table 1 contains a summary of patient characteristics.

Mean patient age was 56 years (range 41-78 years). The mean age of patients who underwent bypass grafting at our hospital was 60.9 years. A mean of 2.3 bypasses were performed per patient (Table 1). The internal mammary artery was routinely used for the left anterior descending artery.

Three of the eight patients required 2 µg/kg/min of dopamine during the surgery. One patient with ischemic cardiomyopathy and ejection fraction of 18% required 5 µg/kg/min of dopamine.

We did not use intraoperative bradycardia.

One patient presented transient ventricular premature beats with no hemodynamic repercussions 12-24 h after surgery. He was treated with lidocaine.

One patient experienced a perioperative inferior infarction with electrocardiographic abnormalities and elevated CK values above 800 U/L and CK-MB at 50 U/L. Two years later we performed catheterization, which showed occlusion of the saphenous vein bypass graft in the right coronary.

Prior to the endarterectomy, one patient had undergone a single internal mammary bypass graft to the left anterior descending artery; catheterization at 36 months verified the patency of the anastomosis (Figure 2) and the absence of new lesions.

Fig. 2. Patency of the anastomosis between the internal mammary artery and the left anterior descending artery in which endarterectomy was performed.

No deaths occurred.

All patients are now asymptomatic and have resumed their activities. In addition, stress tests have been negative for ischemia (Table 1).

The patient with ischemic cardiomyopathy required hospitalization on two occasions during the postoperative period for dose-adjustment of the heart failure medication.

Follow-up lasted from 9 to 64 months.

DISCUSSION

Coronary endarterectomy with aortocoronary bypass grafting is controversial, with rates for mortality of 0%-10%, perioperative infarction of 5%-30%, and anastomosis patency of 38%-100%.^9,11 This variability in outcome, clinical improvement and disappearance of symptoms in 74-95% of endarterectomy patients, makes it impossible to clearly identify the limit between precise indication and excess practice of the procedure. Therefore, surgery should be personalized according to the perioperative findings⁷ and be performed carefully,⁸ since increased troponin-T and CK-MB levels have been reported with coronary endarterectomy.¹²

On-pump or off-pump endarterectomy helps achieve effective revascularization of vessels that otherwise appear to be inoperable. However, we should consider the various techniques, apparent increase in myocardial infarction rates, vessel rupture due to inadequate traction, long-term patency rates below those of vessels without endarterectomy, and mortality rates, in order to offer optimal revascularization in patients who cannot receive percutaneous angioplasty and to provide a surgical option for patients who would otherwise be inoperable.¹³ Since only patients whose symptoms recur are normally catheterized and more than 80% of patients exhibit no long-term symptoms,^14,15 with patency rates above 85%,⁸ it should be remembered that bias does exist.

When endarterectomy is needed during off-pump coronary artery bypass grafting, the procedure can be converted to on-pump surgery and then be completed. However, it is still necessary to evaluate whether or not this conversion would modify the technique. If no change is needed, the surgery should be continued without adding the potential morbidity associated with an on-pump procedure, even in complex cases.¹⁶

CONCLUSION

Simultaneous off-pump coronary artery bypass grafting and endarterectomy is a viable alternative when there is no other option for adequate revascularization, and can achieve effective medium- and long-term clinical improvement in these patients, when performed as recommended herein.

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Correspondence: Dr. G. Careaga Reyna.
División de Cirugía. Hospital de Cardiología,
Centro Médico Nacional Siglo XXI,
Avda. Cuauhtémoc, 330, Col Doctores, 06725 México DF, México.
E-mail: [e-mail]