Minimally invasive coronary revascularization through parasternal incisions without cardiopulmonary bypass

Atrial fibrillation after minimally invasive direct coronary artery bypass surgery

OBJECTIVES

The study compared the adjusted risk for developing atrial fibrillation (AF) after minimally invasive direct coronary artery bypass surgery (MIDCAB) and coronary artery bypass graft surgery (CABG).

BACKGROUND

Atrial fibrillation results in increased morbidity and delays hospital discharge after CABG. Recently, MIDCAB has been explored as an alternative to CABG. Because of differences in surgical approach between the two procedures, the incidence of AF may differ.

METHODS

Randomly selected patients undergoing CABG and MIDCAB were examined. Baseline variables and postoperative course were recorded through review of medical record data.

RESULTS

The MIDCAB patients were younger than CABG patients (64+/-12 vs. 67+/-10, p<0.04) and had less extensive coronary artery disease (53% of MIDCAB vs. 3% of CABG had single-vessel disease, while 15% of MIDCAB vs. 69% of CABG had triple-vessel disease, p<0.001 for overall group comparisons). No other differences in clinical or treatment data were noted. Postoperative AF occurred less often after MIDCAB (23% vs. 39%, p = 0.02). Other significant factors associated with postoperative AF included age (p = 0.0024), prior AF (p = 0.0007), left main disease (p = 0.01), number of vessels bypassed (p = 0.009), absence of postoperative beta-blocker therapy (p = 0.0001), and a serious postoperative complication (p = 0.0018). Because of differences between CABG and MIDCAB patients, multivariate logistic analysis was performed to determine independent predictors of postoperative AF. The type of surgery (CABG vs. MIDCAB) was no longer a significant predictor of postoperative AF (estimated relative risk for AF in CABG vs. MIDCAB patients: 1.57, 95% confidence interval (0.82-2.52).

CONCLUSIONS

Although AF appears to be less common after MIDCAB than after CABG, the lower incidence is due to different clinical characteristics of patients undergoing these procedures.

Coronary revascularization of the circumflex system: different approaches and long-term outcome

BACKGROUND

Minimally invasive direct coronary artery bypass, without cardiopulmonary bypass, through a left lateral thoracotomy approach (lateral MIDCAB), is a safe alternative to coronary artery bypass surgery using cardiopulmonary bypass (on-pump CABG) of the circumflex system via median sternotomy. However, it is unknown whether lateral MIDCAB may yield an improved long-term outcome over the conventional on-pump median sternotomy approach.

METHODS

We compared the perioperative outcomes of patients undergoing lateral MIDCAB (n = 34) versus conventional on-pump CABG of the circumflex system (n = 16) from June 1996 to July 1999. The two groups were similar with respect to baseline characteristics and risk stratification. Patients who required only one or two grafts for complete revascularization were included.

RESULTS

Lateral MIDCAB patients had a lower need than on-pump CABG patients for intraoperative (12% MIDCAB vs 43% on-pump CABG, p = 0.03) and postoperative transfusions (29% vs 69%, p = 0.01), had fewer neuropsychologic changes (0% vs 19%, p = 0.03), and had a lower rate of postoperative atrial fibrillation (12% vs 44%, p = 0.02). Lateral MIDCAB was also associated with a significantly lower postoperative length of stay (5 +/- 2 vs 7 +/- 3 days, p = 0.02). Actuarial survival at a mean period of follow-up of 19 +/- 11 months was 97% for the lateral MIDCAB versus 88% for the on-pump CABG group (p = 0.6). Event-free survival was 88% for lateral MIDCAB versus 81% for on-pump CABG (p = 0.1).

CONCLUSIONS

Lateral MIDCAB may safely be performed in patients with isolated coronary artery disease of the circumflex system with improved early morbidity and an abbreviated hospital stay compared with conventional median sternotomy on-pump CABG.

A xiphoid approach for minimally invasive coronary artery bypass surgery

BACKGROUND

The premise for adopting minimally invasive cardiac surgery techniques for myocardial revascularization is to reduce the patient's morbidity without compromising the efficacy of conventional coronary artery bypass. However, opening the pleura has been a limitation of using these approaches.

AIM

We used the xiphoid approach as an alternative to opening the pleura and to minimize pain after minimally invasive coronary artery bypass surgery.

METHODS

We review our surgical experience in 55 patients who underwent minimally invasive direct coronary artery bypass (MIDCAB) surgery through a xiphoid approach between October 1997 and August 1999. Thoracoscopy (n = 31) or direct vision (n = 24) were used for internal mammary artery (IMA) harvesting. Mean patient age was 67 +/- 10 years and 65% were men. The mean Parsonnet score was 23 +/- 10. Performed anastomoses included left IMA (LIMA) to the left anterior descending (LAD) artery (n = 53), LIMA-to-LAD and saphenous vein graft from the LIMA to the right coronary artery (n = 1), and LIMA-to-LAD and right IMA (RIMA) to right coronary artery (n = 1).

RESULTS

Postoperative complications included atrial fibrillation (12%), acute noninfectious pericarditis (12%), and acute renal failure (5%). Mean postoperative length of stay was 4 +/- 2 days. Angiography was performed in 16 patients and demonstrated excellent patency of the anastomoses. There was no operative mortality. Actuarial survival was 98% in a mean follow-up period of 11 +/- 5 months.

CONCLUSIONS

Minimally invasive coronary artery bypass can be performed safely through a xiphoid approach with low morbidity, mortality, and a relatively short hospital stay.

Coronary Artery Bypass Grafting without Cardiopulmonary Bypass

Between March 1994 and April 1998, 2869 patients underwent coronary artery bypass grafting at our institution. Of these, 415 (14.5%) with a mean age of 54.4 ± 9.9 years were operated on without cardiopulmonary bypass. Internal thoracic artery was used in 402 cases (97%) and the left anterior descending artery was revascularized in all except 1. Distal anastomoses ranged from 1 to 3, with a mean of 1.45 ± 0.58. Major postoperative complications comprised reoperation because of internal thoracic artery spasm in 1 patient, lower extremity ischemia due to intraaortic balloon pumping in 1 patient, revision for excessive bleeding in 3, and perioperative myocardial infarction in another 3. Hospital mortality was 1.2% (5 deaths). Coronary angiography was performed in 38 patients, 1 to 44 months postoperatively. Examination of 56 distal anastomoses revealed a patency rate of 86.1% for internal thoracic artery grafts and 55% for saphenous vein grafts. It was concluded that coronary bypass surgery without cardiopulmonary bypass gave favorable results in the early postoperative period. However, considering the late graft patency rates, either patient selection or the technique should be reevaluated.

Left internal mammary artery grafting to left anterior descending coronary artery by minimally invasive direct coronary artery bypass approach

New surgical techniques for the treatment of the isolated lesion of the left anterior descending coronary artery (LAD) include off-pump surgery, minimal access to the heart, and endoscopic or computer enhanced coronary artery bypass surgery. The term minimally invasive direct coronary artery bypass surgery (MIDCAB) is related to a left-side minithoracotomy, the harvest of the left internal mammary artery (IMA) under direct vision, and an anastomosis performed between IMA and LAD under direct vision, using the technique of mechanical local immobilization by a special device. Alternative techniques include endoscopic harvesting of the IMA, or as a new and still experimental approach, the closed-chest total endoscopic coronary artery bypass grafting (TECAB) with the use of a high tech telemanipulator system. The currently reported results demonstrate the safety of MIDCAB surgery (30-day mortality < 0.5%, perioperative myocardial infarction < 2%, early patency rate between 95% and 98%). Mid-term results after 6 months have shown a patency rate between 94% and 97%, and more than 90% of the patients are without any angina symptoms. Due to this promising results MIDCAB is an alternative treatment for high-grade LAD lesions.

Off-pump revascularization of the circumflex artery: technical aspect and short-term results

BACKGROUND

Beating heart surgery is a technique currently used for revascularization of the anterior and inferior territory. However, revascularization of the circumflex artery is more problematic. With a specific apparatus and surgical technique, we have extended the use of beating heart surgery to more than 90% of patients with multivessel disease, including those necessitating circumflex artery revascularization.

METHODS

Between October 1996 and November 1997, 140 patients underwent beating heart surgery by the same surgeon (R.C.). Among these patients, 111 required reconstruction of the circumflex artery territory and were followed up prospectively. They represent the cohort of patients presented in this study. There were 90 men and 21 women averaging 64+/-9.9 years of age. Mean left ventricular ejection fraction was 55%+/-13.7%, and a significant left main coronary artery disease was present in 27% of the patients. Five patients had prior coronary revascularization.

RESULTS

An average of 3.1+/-0.1 grafts/patient were performed. Complete revascularization was achieved in 95%. Only 1 patient needed conversion to cardiopulmonary bypass because of spontaneous ascending aortic dissection. Perioperative and postoperative bleeding were 446+/-245 mL and 644+/-442 mL, respectively. Homologous transfusions were required in 40% of the patients. Myocardial infarction occurred in 2.7% and operative mortality in 0.7% (1 patient). Average hospital stay was 6.6+/-3.1 days, and no patient exhibited early recurrence of angina. Early coronary angiograms (first 8 patients) demonstrated a 100% patency with 95% freedom from significant stenosis.

CONCLUSIONS

Complete coronary artery revascularization is feasible on the beating heart without the assistance of cardiopulmonary bypass with a low morbidity and mortality and excellent early angiographic results. Long-term follow-ups are needed to substantiate the potential long-term benefits of this technique.

Intraoperative considerations during minimal-access cardiac surgery

The range of minimal-access cardiac surgery approaches has many implications in intraoperative management. A modified anesthetic regimen is required to deal with the type of surgical exposure, hemodynamic instability, whether cardiopulmonary bypass is used, and early extubation. Intraoperative considerations include hemodynamic monitoring, one-lung ventilation, pharmacological stabilization of the myocardium, pacing, hypothermia, bleeding, and rapid emergence with a minimum of postoperative mechanical ventilation. As a result, anesthetic methods and intraoperative management were modified to meet these specific needs of minimally invasive cardiac procedures.

Intraoperative angiography to assess graft patency after minimally invasive coronary bypass

BACKGROUND

Intraoperative angiography was performed to confirm graft patency immediately after minimally invasive coronary bypass operations.

METHODS

In 26 patients who had internal mammary artery grafting, intraoperative coronary angiography was performed with a portable digital fluoroscope.

RESULTS

High-resolution angiograms were obtained in all cases. Angiography documented vasospasm of the graft or native vessel in 9 patients (graft in 3, native in 2, graft and native in 4 others), which responded promptly to intracoronary vasodilators in all. Angiography identified technically unsuspected and clinically silent fixed stenoses (>50%) in 11 patients, attributable to graft kinking in 2, anastomotic obstruction in 6 (total occlusion in 4), and stenosis of the left anterior descending artery just distal to the anastomosis in three cases (total occlusion in one). In 9 of 11 patients, fixed stenoses were sufficiently severe to warrant intraoperative intervention by surgical revision (n = 5) or angioplasty via the graft (n = 4).

CONCLUSIONS

Intraoperative angiography after minimally invasive coronary artery bypass operations can immediately identify dynamic and fixed obstructions and facilitate their prompt treatment, thereby ensuring that each patient leaves the operating room with an optimal surgical result.

Minimally invasive coronary artery bypass grafting: on the beating heart and via limited access

Minimally invasive coronary artery bypass grafting (MICABG) may be achieved by arterial grafting on the beating heart, without cardiopulmonary bypass, and by operations via limited access. The Second Utrecht MICABG Workshop held October 4-5, 1996, focused on beating-heart coronary immobilization, limited-access thoracoscopic and direct-vision mobilization of the internal mammary artery, limited-access left anterior descending coronary artery grafting, and, finally, facilitated distal anastomosis techniques. It has yielded 33 reports in this supplement. The combined, cumulative experience of a number of participants exceeded 3,000 beating-heart cases, including more than 1,000 with arterial grafting through limited access. The average number of anastomoses per patient ranged from 1.0 to 2.0. Therapeutic strategies are evolving, and dedicated instrumentation is being developed. Randomized clinical trials with angiographic follow-up are required to establish that the reduction in invasiveness of coronary bypass grafting is not achieved at the expense of suboptimal quality of the arterial graft and the distal anastomosis.