Asian Cardiovasc Thorac Ann 2007;15:392-395
© 2007 Asia Publishing EXchange Ltd
Coronary Artery Bypass Surgery with On-Pump Beating-Heart Technique
Mohammed Fouda, FRCS
King Fahad Cardiac Center, Riyadh, Saudi Arabia
For reprint information contact: Mohammed Fouda, FRCS, Tel: 966 1 467 9353, Fax: 966 1 467 1581, Email: dr.mfouda{at}gmail.com, King Fahad Cardiac Center, PO Box 7805, Dept. #37 Riyadh-11472, Saudi Arabia.
 |
ABSTRACT
|
|---|
To evaluate the results of on-pump beating-heart coronary bypass grafting, a retrospective study was carried out on 106 patients who had this procedure between 2003 and 2006. There were 87 (82%) men and 19 (18%) women, with a mean age of 60.53 ± 11.97 years. Five (5%) patients had unstable angina, 10 (9%) had a recent myocardial infarction, and 16 (15%) had congestive heart failure. The mean ejection fraction was 40.38% ± 11.46%. The mean cardiopulmonary bypass time was 66.81 ± 31.14 min. The median number of grafts per patient was 3. The median intensive care unit stay was 47 hours, and hospital stay was 7 days. There were 4 (3.8%) deaths. The mean Parsonnet score was 12.75 ± 11.27 and the logistic EuroSCORE was 7.06 ± 8.62. This study shows that the on-pump beating-heart technique is a safe and convenient method for coronary artery bypass grafting.
|
INTRODUCTION
|
|---|
Coronary artery bypass grafting (CABG) with cardioplegia has been considered the gold standard operation for coronary revascularization. However, as a result of improvements in invasive cardiology, the profile of patients referred for CABG has changed significantly over the last decade. Since most patients referred these days have diffuse coronary artery disease and poor ventricles, the global ischemia caused by the conventional technique could be detrimental in them. Although off-pump coronary artery bypass (OPCAB) has been accepted as a reliable alternative to conventional CABG, it is associated with serious hemodynamic changes when a dilated heart is manipulated. Moreover, OPCAB cannot guarantee complete revascularization when the coronary arteries are of very poor quality. In such patients, we routinely use beating-heart CABG with the support of cardiopulmonary bypass (CPB). This retrospective study was undertaken to assess our technique of CABG on a beating heart.
|
PATIENTS AND METHODS
|
|---|
Data from all 106 patients who underwent isolated CABG by the on-pump beating-heart technique in our unit over a period of 3 years from April 2003 were reviewed. Most of the patients were male (87, 82%), and 93 (88%) were Arabs. Tables 1
and 2 summarize their preoperative characteristics. An alarmingly high proportion (71%) of patients were diabetic. Smoking was another common risk factor; 33% of patients were still smoking at the time of surgery. Operations were performed by two consultant cardiac surgeons experienced in this technique. All patients underwent a detailed history review, clinical examination, complete blood analysis, chest radiography, echocardiography, carotid duplex scanning, pulmonary function tests, and coronary angiography before surgery. Recent myocardial infarction was defined as occurring within 8 weeks of operation. Preoperative renal dysfunction was defined as serum creatinine > 200 µmol·L–1. Operative mortality was death occurring within 30 days of operation. A preoperative assessment of the risk of operative mortality was carried out using 3 well-established scoring systems: Parsonnet score, additive EuroSCORE, and logistic EuroSCORE.
Patients were premedicated with lorazepam 2 mg orally the night before surgery, and morphine 0.1 mg·kg–1 intramuscularly 1 hour before the operation. Anesthesia was induced with sufentanil 1–1.5 µg·kg–1, midazolam 0.05–0.1 mg·kg–1, and rocuronium 0.9 mg·kg–1, maintained with infusions of sufentanil 0.2 µg·kg–1·hr–1, midazolam 1.5 µg·kg–1·hr–1, and rocuronium 0.5 mg·kg–1·hr–1, and further supplemented with sevoflurane as required. Anesthetic maintenance was guided by signs of lack of analgesia that correlated with hemodynamic changes. Cardiopulmonary bypass was established with aortic and 2-stage venous cannulas. The systemic temperature was kept normothermic. The CPB circuit was primed with a crystalloid solution with addition of albumin. Heparin was administered in a dose of 300 U·kg–1. Mechanical stabilizers were used, and vessel occlusion was achieved by encircling with silicone rubber bands. Intracoronary shunts were used in vessels with non-critical stenoses. After completion of surgery, all patients were transferred to the cardiac intensive care unit where they underwent invasive hemodynamic monitoring and elective ventilation until ready for extubation. On the first postoperative day, those who did not require ventilation but were not ready for mobilization or still required significant oxygen therapy were transferred to a high-dependency unit; others were transferred to the ward. Any patient who developed a neurological complication had computed tomography of the brain and detailed neurological assessment by a consultant neurologist. Expert psychiatric evaluation was also undertaken in patients who developed neuropsychiatric disturbances. Acute confusional state was defined as agitation, aggressive behavior, or loss of orientation in time or space developing within 1 week of the operation. Transient ischemic attack was defined as any neurological dysfunction that recovered completely over 24 hours. Stroke was defined as any weakness or loss of muscle function affecting day-to-day activities.
The data were acquired from an electronic database (Cascade Cardiac Surgery 2005; Cascade Databases, Pakistan) and exported to an Excel spread sheet. The analysis was performed using SPSS version 10 for Windows (SPSS, Inc., Chicago, IL, USA) and StatsDirect Statistical Software version 2.4.5 (StatsDirect, Cheshire, UK).
|
RESULTS
|
|---|
Table 3 shows the operative and postoperative characteristics. The median duration of intensive care unit stay was much lower than the mean, due to a few patients who had a prolonged stay for various reasons. As a result of limitations on beds available in the ward, the duration of intensive care unit stay in our setting is not entirely based on clinical need; unfortunately, our records cannot differentiate patients who stayed longer for non-clinical reasons. A large proportion of our patients received blood products. Table 4 shows postoperative complications. Three patients had creatinine levels > 200 mmol·L–1 but they improved without dialysis. The causes of death in the 4 patients who died postoperatively were: brain damage in one who had salvage bypass surgery following cardiac arrest during angiography, adult respiratory distress syndrome in 1, and sepsis in 2.
|
DISCUSSION
|
|---|
The pattern of ischemic heart disease has changed dramatically all over the world. The rapidly increasing incidence of diabetes, hypercholesterolemia, and hypertension in most communities, especially in the Asian region, has given rise to more serious and diffuse coronary artery disease. Patients referred for CABG are becoming technically more difficult to treat, and generally have multiple comorbidities. Moreover, the arrival of medicated stents has had a strong impact on coronary bypass surgery. As reported by Ferreira and colleagues,1 medicated stents have shown a potential for reducing the volume of CABG operations by nearly 21%. The situation is even more challenging in Saudi Arabia, and we have observed very similar trends in the pattern of referral for CABG.
Many controlled trials and retrospective studies have proved that the real benefit of OPCAB is observed in high-risk patients.2–4 Midterm results of OPCAB have shown significantly lower hospital morbidity without compromising outcome in the first 1–3 years after surgery, compared to conventional on-pump CABG.5 High-risk patients with multiple comorbidities profit particularly from avoiding CPB, and show significantly lower hospital mortality.6 The study by Kirali and colleagues7 demonstrated that patients with poor left ventricular (LV) function recover more quickly after OPCAB compared to those who undergo conventional CABG, although the mortality rates and improvement in LV function were similar.
Due to the reported benefits of OPCAB, many surgeons tried to apply this technique without discretion, often resulting in emergency conversion to the conventional technique. Such a situation is a serious risk factor for operative mortality. Edgerton and colleagues8 have shown that congestive heart failure is a significant risk factor for emergency conversion. These patients had a significantly higher incidence of postoperative cardiac arrest, multiorgan failure, vascular complications, perioperative myocardial infarction, and death. On-pump beating-heart CABG eliminates intraoperative global myocardial ischemia and should theoretically be the technique of choice for surgical revascularization in patients with recent acute myocardial infarction. Izumi and colleagues9 found significantly lower mortality, creatine kinase-MB levels, and incidence of renal failure, as well as a tendency for less inotropic support and shorter duration of mechanical ventilation in the on-pump beating-heart group compared to conventional CABG.
This observation was reiterated by Edgerton and colleagues10 who compared the outcomes after OPCAB, conventional CABG, and on-pump beating-heart CABG. Their results strongly suggest that normothermic CPB with a beating heart is safe and efficacious, and may be the method of choice for patients in cardiogenic shock requiring resuscitation or with previous CABG surgery, recent myocardial infarction, a low ejection fraction, or unstable arrhythmias. On-pump beating-heart CABG is particularly effective in protecting myocardial function in patients with severe LV dysfunction. This beneficial effect is further augmented by the fact that this technique enables complete revascularization in the presence of enlarged LV size and impaired LV function.11
Another very challenging subset of patients requiring revascularization includes those who have end-stage coronary artery disease. They are not suitable for CABG by the conventional technique due to poor LV function, and they also have suboptimal revascularization by OPCAB due to technical difficulties. In our practice, these patients are a growing proportion of the cases considered for revascularization.2 They are the potential beneficiaries of the on-pump beating-heart technique as it combines the benefits of both OPCAB and the arrested heart procedure. In this subset, the early and midterm survival, morbidity, and improvement of LV function have shown clear benefits from the on-pump beating-heart technique.12 The mortality and morbidity in this observational study demonstrate that the on-pump beating-heart technique can provide a safe and convenient method for CABG.
|
ACKNOWLEDGMENTS
|
|---|
I appreciate the help and support of Dr. Anjum Jalal, FRCS-CTh for data analysis and preparation of this manuscript.
|
REFERENCES
|
|---|
- Ferreira AC, Peter AA, Salerno TA, Bolooki H, de Marchena E. Clinical impact of drug-eluting stents in changing referral practices for coronary surgical revascularization in a tertiary care center. Ann Thorac Surg 2003;75:485–9.[Abstract/Free Full Text]
- Mack MJ, Pfister A, Bachand D, Emery R, Magee MJ, Connolly M, et al. Comparison of coronary bypass surgery with and without cardiopulmonary bypass in patients with multivessel disease. J Thorac Cardiovasc Surg 2004;127:167–73.[Abstract/Free Full Text]
- Meharwal ZS, Mishra YK, Kohli V, Bapna R, Singh S, Trehan N. Off-pump multivessel coronary artery surgery in high-risk patients. Ann Thorac Surg 2002;74:S1353–7.[Abstract/Free Full Text]
- Velissaris T, Tang AT, Murray M, Mehta RL, Wood PJ, Hett DA, et al. A prospective randomized study to evaluate stress response during beating-heart and conventional coronary revascularization. Ann Thorac Surg 2004;78:506–12.[Abstract/Free Full Text]
- Angelini GD, Taylor FC, Reeves BC, Ascione R. Early and midterm outcome after off-pump and on-pump surgery in Beating Heart Against Cardioplegic Arrest Studies (BHACAS 1 and 2): a pooled analysis of two randomised controlled trials. Lancet 2002;359:1194–9.[Medline]
- Deuse T, Detter C, Samuel V, Boehm DH, Reichenspurner H, Reichart B. Early and midterm results after coronary artery bypass grafting with and without cardiopulmonary bypass: which patient population benefits the most? Heart Surg Forum 2003;6:77–83.[Medline]
- Kirali K, Rabus MB, Yakut N, Toker ME, Erdogan HB, Balkanay M, et al. Early- and long-term comparison of the on- and off-pump bypass surgery in patients with left ventricular dysfunction. Heart Surg Forum 2002;5:177–81.[Medline]
- Edgerton JR, Dewey TM, Magee MJ, Herbert MA, Prince SL, Jones KK, et al. Conversion in off-pump coronary artery bypass grafting: an analysis of predictors and outcomes. Ann Thorac Surg 2003;76:1138–43.[Abstract/Free Full Text]
- Izumi Y, Magishi K, Ishikawa N, Kimura F. On-pump beating-heart coronary artery bypass grafting for acute myocardial infarction. Ann Thorac Surg 2006;81:573–6.[Abstract/Free Full Text]
- Edgerton JR, Herbert MA, Jones KK, Prince SL, Acuff T, Carter D, et al. On-pump beating heart surgery offers an alternative for unstable patients undergoing coronary artery bypass grafting. Heart Surg Forum 2004;7:8–15.[Medline]
- Gulcan O, Turkoz R, Turkoz A, Caliskan E, Sezgin AT. On-pump/beating-heart myocardial protection for isolated or combined coronary artery bypass grafting in patients with severe left ventricle dysfunction: assessment of myocardial function and clinical outcome. Heart Surg Forum 2005;8:E178–3.[Medline]
- Prifti E, Bonacchi M, Giunti G, Frati G, Proietti P, Leacche M, et al. Does on-pump/beating-heart coronary artery bypass grafting offer better outcome in end-stage coronary artery disease patients? J Card Surg 2000;15:403–10.[Medline]
TOP
ABSTRACT
INTRODUCTION
