Abstract

There is an increase in cases with complex, multisegmental left anterior descending (LAD) coronary artery lesions in coronary artery bypass graft (CABG) surgery. In these cases, further reconstructive surgical procedures are needed for complete revascularization. In four cases (3 males, 1 female, mean age 58±3.3 years) with multisegmental LAD lesions, extra surgical intervention was employed to the LAD artery in conjunction with standard coronary surgical procedures between January 2008 and September 2010. All cases presented with class 3 or 4 stable angina pectoris. In all cases, the surgical procedure consisted of standard cannulation followed by CABG under cardiopulmonary bypass. In cases with complex multisegmental LAD lesions, a short saphenous vein graft was bridged between the mid and distal portions of the LAD as a new technique. The prepared left internal mammarian artery was anastomosed to this bridge which was created over the LAD. The remaining coronary anastomoses were performed with the standard technique. The postoperative period passed without any problem in all patients. We believe that this is a successful technique for providing complete revascularization in patients with complex, multisegmental LAD lesions.

The basic aim of surgical interventions in coronary artery disease is to revascularize the viable myocardial tissue that is supplied by the occluded or stenotic coronary artery.[1] Complete revascularization is not feasible with standard bypass techniques in the presence of multiple and complex lesions. In particular, residual lesions in the left anterior descending artery (LAD) are an important parameter affecting perioperative and late period mortality.[2] Thus, to establish sufficient distal run-off, an endarterectomy or further reconstructive procedures are required.[3] We present four cases with multisegmental LAD lesions in which we performed a bridge between the mid and distal LAD segment with a saphenous vein graft which was anastomosed to the left internal mammary artery (LIMA), (Figure 1, 2).

Figure 1: Intraoperative view of the bridge.

Figure 2: Illustration of the bridge.

Methods

With the aforementioned technique, both the mid and distal segments of the multisegmental stenotic LAD were perfused. Three of the cases were male and one case was female with an average age of 58±3.3 years. All patients were in class 3 or 4 stable angina pectoris. Preoperative demographics findings of the patients were demonstrated in table 1. All cases had borderline left ventricular ejection fraction (EF) values. The mean left ventricular ejection fraction (LVEF) was 41±4%. The internal mammary artery and saphenous vein were used as grafts, and the surgical procedure was standard cannulation and coronary artery bypass graft (CABG) surgery under cardiopulmonary bypass (CPB). During CPB, moderate hypothermia was instituted and first cold cardioplegia, intermittent cold blood cardioplegia, and terminal warm blood cardioplegia were applied. The other diseased coronary arteries were revascularized, and the calcific sites of the LAD were identified. Two arteriotomies were made at the mid and distal segment of the LAD, and a bridge was formed with a short saphenous vein segment. The internal mammary artery was anastomosed to this bridge (Figure 1, 2). To ensure the flow to both sides through a saphenous vein graft, a valveless part of the saphenous graft was used. Neither endarterectomy nor saphenous patch plasty was used in the patients. The postoperative period was normal with regard to the hemodynamics and cardiac enzymes. All patients were discharged without morbidity.

Table 1: Preoperative demographics of the patients

Results

Myocardial ischemia was monitored with electrocardiography (ECG) and enzyme changes (cTnI) in the perioperative and postoperative periods, and none of the patients displayed significant changes in their ECG or enzyme levels. Ventricular arrhythmia was observed in two patients postoperatively. The average intensive care unit (ICU) stay was 45±5.2 hours, and the average hospital stay was 7.2±0.4 days. There was no early mortality. All of the patients were in sinus rhythm, and none displayed ischemic changes in their ECGs or enzyme levels analyze at their postoperative outpatient visits. Perioperative and postoperative findings of patients are illustrated in table 2.

Table 2: Preoperative and postoperative findings of the patients

Discussion

The increase in percutaneous interventional procedures has changed the anatomic profile of lesions among surgically revascularized patients. Patients that are not correctable with percutaneous intervention and who require surgery present with more advanced and difficult lesions. Therefore, in patients with multisegmental lesions that are not suitable for grafting, complex surgical techniques are mandated.[4]

The primary goal in coronary surgery is complete revascularization. Left anterior descending artery revascularization is very important and, because of its direct relationship with early and late mortality, decreasing recurrent angina, and related deaths, the LIMA must be the choice of bypass graft.[5] In multisegmental and diffuse coronary artery disease of the LAD, residual lesions due to incomplete revascularization are among the most important parameters for perioperative and postoperative mortality.[6] If the coronary artery disease is not multisegmental and diffuse, arterial grafts can be anastomosed to the appropriate site directly. Nevertheless, when lesions are calcific, diffuse, and multisegmental in nature, different techniques are essential for complete revascularization. Direct LIMA anastomosis may be technically feasible in the presence of calcific and multisegmental diffuse lesions, although the long-term results are disappointing. To overcome this problem, vein patch with or without endarterectomy may be used.[7,8] There is an ongoing debate over two techniques of coronary artery endarterectomy. The closed endarterectomy technique requires a small arteriotomy, and its reconstruction is easier. The greatest risk involved in this technique is the incomplete removal of distal plaque leading to a postoperative decrease in septal branch blood flow.[9,10] On the other hand, in the open technique, this disadvantage doesn't exist because of the complete removal of the plaque in the main artery and its septal branches.[9,11] In the open endarterectomy technique with saphenous vein patch, the arteriotomy is extended distally to the beginning of the normal lumen, and the endarterectomy is performed on this diseased segment. A variation is reconstruction with saphenous vein patch after endarterectomy and the saphenous vein graft or LIMA anastomosed to this patch.[12] Some surgeons prefer proximal IMA bypass and saphenous vein patch plasty for an existing distal stenotic lesion.[13]

Residual obstruction, intimal flap thrombosis, and atheroemboli are the main causes of ischemia after endarterectomy-related procedures.[14] Coronary artery bypass graft surgery with coronary artery endarterectomy has higher morbidity and mortality rates compared with standard CABG surgeries.[15,16] The mortality rate is even higher when the LAD is the artery on which the endarterectomy is performed.[17,18] Studies have shown a 2-8% mortality rate in the early postoperative period in such patients. Qureshi et al.[19] have noted the in-hospital mortality as 4% among patients who underwent an endarterectomy on the left coronary artery system.

All techniques are time consuming and prolong the myocardial ischemic period.[20] These drawbacks have led some authors to advocate the bridge technique (multiple sequential anastomosis) for patients with multisegmental stenosis at the LAD system.[21,22] Technical difficulties arise in multiple sequential anastomosis with a single graft from adjusting the length of the graft in order to avoid kinking or tension. With our technique, we not only avoid the risk of endarterectomy but also decrease the myocardial ischemic time. Furthermore, the difficulty with arranging the length of the single graft in a multisequential anastomosis technique is absent if our technique is used.

The anatomic lesions suitable for that we have mentioned above are rarely seen. Although our series is small, with the good result of our cases and easy implementation, we strongly advocate that this technique should be preferred in diffuse multisegmental LAD coronary artery pathologies.

Declaration of conflicting interests
The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Funding
The authors received no financial support for the research and/or authorship of this article.

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