Coronary Artery Bypass Grafting Using the Rama Technique, A Method of Coronary Stabilization: Short-Term Results

(#1999-9908 ... May 21, 1999)

F. Jault, MD, E. Coignard, MD, A. Rama, MD, E. Vaissier, MD, N. Bonnet, MD, A. Pavie, MD, I. Gandjbakhch, MD

INTRODUCTION

Direct coronary revascularization on the beating heart is supposed to decrease medical costs and morbidity related to extracorporeal circulation and is currently performed more often than conventional surgery. Mechanical stabilization allows the surgeon to perform coronary anastomoses, as well, with conventional bypass surgery [Poirier 1999]. In our unit, we use a particular method of coronary stabilization, which is inexpensive and easy to perform. This study summarizes the short-term results of this method, called the "Rama technique", in 78 patients.

MATERIALS AND METHODS

From May 1997 to July 1998, 78 patients underwent off-pump coronary artery bypass grafting (CABG) using a particular coronary stabilizer. Patients with acute myocardial infarction, acute coronary angioplasty failure, cardiogenic shock, or prior CABG were excluded. Patients with diffuse atheromatous disease, intramyocardial left anterior descending artery (LAD), or heavily calcified coronary arteries were also excluded. The preoperative characteristics of the patients are listed in Table 1. Echocardiographic data were recorded in 44 patients. The mean left ventricular end-diastolic diameter was 52.5 ± 6.6 mm.

Rama Technique

All patients were operated on by median sternotomy. Exposure of the distal branches of the right coronary artery was obtained by minimal traction on stitches passed through the inferior wall of the right ventricle. Exposure of the circumflex distal branches was obtained by traction on stitches passed through the left ventricular myocardium, below the coronary artery target. Placing the patient in a Trendelenburg position avoided hypotension as shown by Gründeman [Gründeman 1997].

Cardiac wall stabilization was achieved by stitches passed through the myocardium and knotted on a patch of dacron [see Figure 1 :226:]; A hole made in the middle of the patch exposes the target artery. A temporary coronary shunt was most often used for the distal anastomoses. Proximal venous anastomoses were performed using a single partial occlusion clamp application.

Measurements of serum levels of cardiac troponin I were obtained 6 hours after surgery and daily for the next 2 days by an enzyme immunoassay. The limit of detection is 0 ng/mm. Transesophageal echocardiogram was recorded immediately after surgery and repeated when necessary. Perioperative myocardial infarction was diagnosed in the presence of 1 or both of the following criteria: the development of new Q waves on the electrocardiogram, the appearance of a new abnormality in segmental wall motion on the echocardiogram, or a troponin I level more than 2 ng/ml.

Follow-Up and Statistical Analysis

The mean follow-up was 18 months (range: 10 months to 2 years). Follow-up information was obtained by contacting patients and referring cardiologists. Clinical outcome, exercise testing, and coronary arteriography were assessed. All data are presented as percentages or as mean ± standard deviation.

RESULTS

Twelve patients received 1 graft, 32 received 2 grafts, 30 received 3 grafts, and 4 received 4 grafts. There was an average number of 2.33 grafts per patient [see Table 2 :228:]. The left internal mammary artery (LIMA) graft was used in 68 patients, the right (RIMA) graft in 5 patients, both LIMA and RIMA grafts in 2 patients, and the gastroepiploic branch in 1 patient.

Mean troponin I level was 1.7 ng/ml at 6 h and 1.4 ng/ml at 24 h. There were no perioperative myocardial infarctions. Ten of the patients (12.8%) needed inotropic support during the first postoperative day. No neurological complication occurred. Excessive bleeding occurred in only 2 patients.

Operative mortality was 1.3%. One patient died of hemodynamic failure. Two patients were lost to followup. Two patients died, 1 of aortic dissection and 1 of sudden death. We now follow 73 patients and 71 are symptom free.

Exercise tests were performed on 60 patients and revealed no ischemia. Coronary angiography was performed systematically during the first postoperative month in 20 patients. All internal mammary grafts were patent [Table 3 :229:].

DISCUSSION

Coronary artery bypass grafting on the beating heart requires optimal anastomotic site stabilization and good exposure of the left ventricular posterolateral wall. Coronary stabilization can be achieved by several devices (as described by several authors): silicone rubber tape around the coronary arteries [Grundry 1998], a pulling-pushing device [Cartier 1998] and the Octopus [Jansen 1998, Spooner 1998, Hart 1999].

The technique described here is easily performed, inexpensive, and efficacious. The exposure of the posterolateral wall, which was very difficult to obtain at the beginning of this type of surgery, is now feasible. One can use pericardial traction as described by Cartier [Cartier 1998] or traction on stitches passed below the target area, as with our procedure. The Trendelenburg maneuver avoids drop in stroke volume when lifting the beating heart, as shown by Gründeman [Gründeman 1997] and is widely used. The inferior wall is more easily exposed. These artifices make bypasses of the circumflex branches and of the right coronary distal branches possible, and more complete revascularization is now achieved. Tasdemir [Tasdemir 1998] reported 22 grafts of the circumflex branches and seven of the distal branches of the right coronary artery among 2,052 patients operated on between 1993 and 1996. In our data on 78 patients, 40 grafts on the obtuse marginal branch, two grafts on the posterolateral branch and 14 grafts on the right posterior descending artery were performed. The average number of grafts per patient is 2.33 in this data, 2.7 in Cartier's report [Cartier 1998], and 1.8 in Spooner's report [Spooner 1998].

Some limitations remain, however. We think that patients with intramyocardial LAD or diffuse atheromatous disease are not good candidates for off-pump grafting. As for patients with cardiomegaly and/or prior bypass surgery, we need more data to determine if the technique would be beneficial. Such patients have been excluded in this report. No postoperative myocardial infarction occurred in these selective patients. Serum troponin I concentration increased in all the patients, as after every cardiac operation [Katus 1991, Pelletier 1994] but the peak release was lower than 2 ng/ml in all 78 patients.

The current quality of anastomoses seems excellent. From July 1989 to July 1990, Grundry [Grundry 1998] reported a 34% patency rate for off-pump grafts versus a 72% rate for traditional CABG grafts. However, newer stabilization devices have enhanced anastomotic quality as shown by Jansen [Jansen 1998] and Poirier [Poirier 1999]. In this data, 19 mammary grafts were normal on early angiographic controls. The short-term clinical results are good with 71 patients symptom free.

The technique of coronary stabilization described in this data, called "Rama technique", which is inexpensive and easily performed, has good short-term results.

AUTHOR/ARTICLE INFORMATION

Presented at the Second Annual Meeting of the International Society for Minimally Invasive Cardiac Surgery, Palais dés Congres, Paris, France, May 21-22, 1999

Reprint requests to: E. Coignard, MD, Groupe Hospitalier, Pitié-Salpêtrière, 47-83 Boulevard de l'Hôpital, 75751 Paris Cedex 13

Submitted on: Presented at the Second Annual Meeting of the International Society for Minimally Invasive Cardiac Surgery, Palais dés Congres, Paris, France, May 21-22, 1999.

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