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

Hybrid Coronary Artery Revascularization: A Review and Current Evidence

OBJECTIVE

The role of hybrid coronary revascularization (HCR), which utilizes the combination of minimally invasive surgical coronary artery bypass grafting of the left anterior descending artery and percutaneous coronary intervention (PCI) of non-left anterior descending vessels to treat multivessel coronary artery disease, is expanding. We set out to provide a review of this technology.

METHODS

We conducted a retrospective analysis of all minimally invasive hybrid operations performed at our institution from September 2004 to December 2018. An effective analysis comparing patients undergoing HCR vs off-pump or on-pump surgical coronary artery revascularization was undertaken using an adjusted analysis with inverse-probability weighting based on the propensity score. Outcomes that were assessed include death, myocardial infarction, stroke, atrial fibrillation, renal failure, requirement of blood transfusion, conversion to open procedure (in the hybrid group), length of stay in intensive care unit, and total length of stay in hospital. Intention-to-treat analysis was performed. An up-to-date literature review of HCR complements this study.

RESULTS

Since 2004 a total of 191 consecutive patients (61.4±11.1 years; 142 males and 49 females) underwent HCR (robotic-assisted coronary artery bypass graft of the left internal thoracic artery to the left anterior descending coronary artery (LAD) and PCI of a non-LAD vessel) in a single- or double-stage fashion. Successful HCR occurred in 183 of the 191 patients (8 patients required intraoperative conversion to conventional coronary bypass). From our comparative analysis and literature review we found no significant difference between HCR and coronary artery bypass grafting groups with respect to in-hospital and 1-year follow-up.

CONCLUSIONS

Current evidences suggest that HCR is a feasible, safe, and effective coronary artery revascularization strategy in selected patients with multivessel coronary artery disease.

Off-pump versus on-pump coronary artery bypass graft surgery: differences in short-term outcomes and in long-term mortality and need for subsequent revascularization

BACKGROUND

Off-pump coronary artery bypass graft surgery (OPCAB) has been performed for many years, but its use is increasing in frequency, and it remains an open question whether OPCAB is associated with better outcomes than on-pump coronary artery bypass graft (CABG) surgery.

METHODS AND RESULTS

New York State patients who underwent either OPCAB with median sternotomy (13 889 patients) or on-pump CABG surgery (35 941 patients) between 2001 and 2004 were followed up via New York databases. Short- and long-term outcomes were compared after adjustment for patient risk factors and after patients were matched on the basis of significant predictors of type of CABG surgery. OPCAB had a significantly lower inpatient/30-day mortality rate (adjusted OR 0.81, 95% confidence interval [CI] 0.68 to 0.97), lower rates for 2 perioperative complications (stroke: adjusted OR 0.70, 95% CI 0.57 to 0.86; respiratory failure: adjusted OR 0.80, 95% CI 0.68 to 0.93), and a higher rate of unplanned operation in the same admission (adjusted OR 1.47, 95% CI 1.01 to 2.15). In the matched samples, no difference existed in 3-year mortality (hazard ratio 1.08, 95% CI 0.96 to 1.22), but OPCAB patients had higher rates of subsequent revascularization (hazard ratio 1.55, 95% CI 1.33 to 1.80). The 3-year OPCAB and on-pump survival rates for matched patients were 89.4% and 90.1%, respectively (P=0.20). For freedom from subsequent revascularization, the respective rates were 89.9% and 93.6% (P<0.0001).

CONCLUSIONS

OPCAB is associated with lower in-hospital mortality and complication rates than on-pump CABG, but long-term outcomes are comparable, except for freedom from revascularization, which favors on-pump CABG.

Deep pericardial suture vs apical suction for off-pump bypass grafting

Hemodynamic changes during heart luxation and stabilization are major problems in off-pump coronary artery bypass surgery. The hemodynamic effects of an apical suction device were compared with those of the classic posterior pericardial suture in 45 patients with multivessel coronary disease undergoing off-pump coronary artery bypass. Mean age was 63.78 +/- 8.11 years; 31 patients were male and 14 were female. Transesophageal Doppler echocardiography was used for hemodynamic monitoring. All hemodynamic parameters were significantly better when the apical suction device was used to position the heart for anastomoses on the posterior descending and circumflex arteries.

Temporary coronary artery occlusion during off-pump coronary artery bypass grafting with the new poloxamer P407 does not cause endothelial dysfunction in epicardial coronary arteries

OBJECTIVE

The aim of this study was to assess the efficacy of the novel reversible thermosensitive gel poloxamer 407 for occlusion of the coronary vessel necessary for minimally invasive operations and its effects on coronary endothelium.

METHODS

Domestic swine were submitted to occlusion of the left anterior descending or right coronary artery using the poloxamer. The left and right internal thoracic arteries were used as grafts to perform coronary artery bypasses. Animals were humanely killed after 3 hours of perfusion (acute; n = 8) or 3 days (subacute; n = 6). The vascular reactivity of coronary artery was evaluated in response to serotonin and bradykinin. Histologic studies were performed to analyze cardiomyocyte necrosis and endothelial coverage.

RESULTS

The gel led to an occlusion of 7.8 +/- 2.2 minutes. Concentration-response curves of occluded coronary segments showed no difference of endothelium-dependent relaxations in both operated groups (P < .05 vs control). Histologic studies demonstrated the absence of cardiomyocyte necrosis after coronary artery occlusion in the acute group; a small infarct zone was detected in 1 animal in the subacute group, resulting from an occlusion of the first diagonal branch. The endothelial layer coverage was preserved in both groups.

CONCLUSION

The poloxamer 407 represents a promising technique for obtaining hemostasis at the site of anastomosis during construction of bypasses during beating heart coronary artery surgery, without damage to the endothelium or ischemic consequence.

Midterm Results of Off-Pump Coronary Artery Bypass Surgery in 136 Patients: An Angiographic Control Study

BACKGROUND

Off-pump coronary artery bypass surgery may provide an alternative form of surgical revascularization by avoiding the complications of cardiopulmonary bypass (CPB). This study summarizes the midterm results of 136 off-pump bypass surgery patients.

METHODS

Between January 2000 and March 2002, out of 178 surgical myocardial revascularizations, 136 (76.4%) were off-pump bypass surgery. Complete revascularization was done and especially arterial grafts were used. All patients were followed clinically and with treadmill test for 2 years. Average control angiography was performed at the end of 2-year follow-up.

RESULTS

Of all the patients, 56.7% were male and the mean age of the patients was 63.6 +/- 7.4 years. A total of 481 anastomoses were performed-136 (28.27%) to the left anterior descending artery (LAD), 135 (28.07%) to the circumflex coronary artery (Cx) branches, 102 (21.20%) to the right coronary artery (RCA), 108 (22.46%) to the Di. The mean graft number was 3.46. We used 96.6% of patients' left internal mammarian artery (LITA), 29.2% radial artery (RA), 4.4% right internal thoracic artery (RITA), and 100% saphenous vein. There were ischemic changes within 12 patients. All ischemic changes came back to normal within 4 and 18 hours, postoperatively. Mean extubation time was 5.36 +/- 2.23 hours, mean stay in intensive care unit was 17.53 +/- 3.15 hours, mean hospital stay was 5.03 +/- 1.29 days. The LITA patency was 99.25%, RA patency was 97.84%, RITA patency was 100%, and saphenous vein patency was 91.79% with control angiography.

CONCLUSION

Off-pump coronary artery bypass graft (CABG) is efficient procedure with lower index of mortality, morbidity, ICU stay, hospital stay, good wound healing, early socialization, and results in lower costs.

Redo Minimally Invasive Direct Coronary Artery Bypass Grafting

BACKGROUND

Conventional redo coronary artery bypass grafting is associated with an increased risk of mortality and morbidity as a result of manipulation of patent grafts, mediastinitis, and the presence of pericardial adhesions. Minimally invasive direct coronary artery bypass grafting may be an alternative approach in selected patients.

METHODS

From January 1997 to October 2003, 46 patients (mean age, 66 +/- 7.4 years) underwent minimally invasive direct coronary artery bypass grafting using the left internal thoracic artery to the left anterior descending artery on the beating heart as a reoperation. Patients after previous cardiac operation by means of median sternotomy without use of the left internal thoracic artery presenting with a significant left anterior descending artery stenosis ("culprit lesion") were included. Predicted mortality was 13.6% (range, 2.4% to 72.8%) as calculated by the logistic Euroscore; ejection fraction was 0.531 (range, 0.14 to 0.81). Surgical results were analyzed for mortality, morbidity, duration of the procedure, hospital stay, and event-free survival.

RESULTS

Mean operating time was 103 +/- 34 minutes. There were two in-hospital deaths (4.6%), one for malignant ventricular arrhythmia (Euroscore, 60.9%) and the second as a result of severe gastrointestinal bleeding (Euroscore, 29.2%). One patient (2.3%) was successfully reoperated on because of perianastomotic hematoma using the same approach after 6 days. Patients were discharged after 9.4 +/- 2.6 days. There were no other serious adverse events, no stroke, and no myocardial infarction. During follow-up (37 +/- 21 months, complete in 92.1%), 1 patient experienced angina and 6 patients died. The actuarial 4-year survival is 74.8% (95% confidence interval, 51% to 92%), and the actuarial 4-year event-free survival including freedom from angina, major adverse cardiac events, and reintervention is 81% (95% confidence interval, 54% to 97%).

CONCLUSIONS

Minimally invasive direct coronary artery bypass grafting can be considered as an alternative approach for redo coronary artery bypass grafting in selected patients.

Concomitant aortoaxillary bypass and coronary artery bypass grafting

The optimal revascularization strategy for patients with subclavian and coronary artery disease has not been established. This study assessed the mid-term clinical outcome of concomitant aortoaxillary bypass and coronary artery bypass grafting in 5 patients. A ring-reinforced polytetrafluoroethylene graft was attached to the ascending aorta and led to the proximal segment of the axillary artery via the pleural cavity. Patients were followed up for 2-10 years (mean, 5.4 +/- 3.4 years). Postoperative aortography and angiography demonstrated patent aortoaxillary and coronary bypass grafts in the short-term follow-up of all patients. Two patients with Takayasu aortitis needed re-operations for recurrent angina and annuloaortic dilatation. Another patient required removal of the aortoaxillary bypass graft because of infection, and subsequently underwent a left femoroaxillary bypass one year after the original procedure. Subclavian steal phenomenon did not occur. Aortoaxillary bypass with coronary artery bypass may be an effective option for patients with co-existing subclavian and coronary artery disease.

A comparison of short- and long-term outcomes after off-pump and on-pump coronary artery bypass graft surgery with sternotomy

OBJECTIVES

This study was designed to compare in-hospital mortality and complications and three-year mortality and revascularization for off-pump and on-pump coronary artery bypass graft (CABG) surgery after adjusting for patient risk.

BACKGROUND

The use of off-pump CABG surgery has increased tremendously in recent years, but little is known about its long-term outcomes relative to on-pump CABG surgery, and most studies have been very small.

METHODS

Short- and long-term outcomes (inpatient mortality and complications, three-year risk-adjusted mortality, and mortality/revascularization) were explored for patients who underwent off-pump CABG surgery (9135 patients) and on-pump CABG surgery (59044 patients) with median sternotomy from 1997 to 2000 in the state of New York.

RESULTS

Risk-adjusted inpatient mortality was 2.02% for off-pump versus 2.16% for on-pump (p = 0.390). Off-pump patients had lower rates of perioperative stroke (1.6% vs. 2.0%, p = 0.003) and bleeding requiring reoperation (1.6% vs. 2.2%, p < 0.001) and higher rates of gastrointestinal bleeding, perforation, or infarction (1.2% vs. 0.9%, p = 0.003). Off-pump patients had lower postoperative lengths of stay (median 5 days vs. 6 days, p < 0.001). On-pump patients had higher three-year survival (adjusted risk ratio [RR] =1.086, p = 0.045) and higher freedom from death or revascularization (adjusted RR = 1.232, p < 0.001). When analyses were limited to 1999 to 2000, the two-year adjusted hazard ratio for survival was not significant (adjusted RR = 0.99, p = 0.81).

CONCLUSIONS

On-pump patients experience better long-term survival and freedom from revascularization than off-pump patients. However, the survival benefit from on-pump procedures was no longer present in the last two years of the study.

Lung isolation during port-access cardiac surgery: double-lumen endotracheal tube versus single-lumen endotracheal tube with a bronchial blocker

OBJECTIVE

The purpose of this study was to compare the use of a double-lumen endotracheal tube to a single-lumen tube combined with a bronchial blocker for lung isolation during Port-Access cardiac surgery.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Tertiary care university hospital.

PARTICIPANTS

Thirty-two patients undergoing Port-Access cardiac surgery via a right minithoracotomy.

INTERVENTIONS

Patients were randomized to intubation with either a left-sided double-lumen tube (double-lumen group) or a single-lumen tube with concomitant use of a bronchial blocker (blocker group). Comparisons between groups included (1) intubation time, (2) number of laryngoscopy attempts, (3) time required for tube exchange at the end of the operation, and (4) surgical satisfaction with the lung deflation (1-5 scale: 5 = excellent).

MEASUREMENTS AND MAIN RESULTS

The initial intubation time was similar between groups (118 +/- 82 seconds, double-lumen v 144 +/- 32 seconds, blocker; p = 0.2781). An additional 105 +/- 37 seconds was needed to exchange the double-lumen tube at the end of the operation. The double-lumen group also required more laryngoscopy attempts compared with the blocker group (2.3 +/- 0.6, double-lumen v 1.1 +/- 0.4, blocker; p = 0.0001). The lung deflation was better in the double-lumen group (5 [4-5], double-lumen v 4 [3-5], blocker, p = 0.0414).

CONCLUSIONS

Compared with a single-lumen tube/bronchial blocker combination the double-lumen endotracheal tube required more laryngoscopy attempts and additional time to replace the tube at the end of the case but resulted in slightly better overall lung deflation.

Controlled intermittent asystole cardiac therapy induced by pharmacologically potentiated vagus nerve stimulation in normal and hibernating myocardium

BACKGROUND

Pharmacologically potentiated electrical stimulation of the right vagus nerve achieves controlled intermittent asystole cardiac therapy. The present study examined pathophysiologic consequences of repetitive intermittent asystoles on contractile function, myocardial blood flow, and vagus nerve function and morphology.

METHODS

Open-chest anesthetized canines, with either normal left anterior descending (LAD) coronary arteries (n = 8) or severely stenotic LADs (n = 8), received pharmacologic pretreatment with pyridostigmine (0.5 mg/kg), propranolol (80 microg/kg), and verapamil (50 microg/kg) before vagus nerve stimulation. Time-matched control animals with normal (n = 4) or severely stenotic LADs (n = 6) received drugs but no vagus nerve stimulation. The vagus nerve was stimulated for 12 seconds ("on") and rested for 15 seconds ("off"). This algorithm was repeated for 15 on-off cycles, simulating using controlled intermittent asystole during the placement of 15 sutures in a distal coronary anastomosis. This 15-cycle sequence was repeated twice more, simulating a three-vessel bypass.

RESULTS

Normal coronary arteries: Ninety minutes after three sets of controlled intermittent asystole, LAD blood flow was unchanged from base line (36.6 +/- 4.5 versus 33.0 +/- 4.2 mL/min, p = 0.4), and global left ventricular performance (impedance catheter, end-systolic pressure-volume relations) was similar to baseline (7.4 +/- 1.2 versus 7.2 +/- 1.0 mm Hg/mL, p = 0.1). Left anterior descending coronary artery stenosis model: Ninety minutes after CIA, there were no significant differences versus control animals in regional LAD blood flow (27 +/- 4 versus 29 +/- 5 mL/min, p = 0.4) or fractional shortening of LAD myocardium (sonomicrometry; 6.2% +/- 1.8% versus 5.4% +/- 1.2%, p = 0.1). Vagus nerve conduction and morphology were unchanged from baseline.

CONCLUSIONS

Repetitive controlled intermittent asystole does not impair poststimulation coronary blood flow, cardiac contractile function, or vagus nerve function. Controlled intermittent asystole may be useful to facilitate off-pump or endoscopic coronary artery bypass grafting.

Risk of iron overload is decreased in beating heart coronary artery surgery compared to conventional bypass

Conventional cardiopulmonary bypass surgery (CCPB) increases the iron loading of plasma transferrin often to a state of plasma iron overload, with the presence of low molecular mass iron. Such iron is a potential risk factor for oxidative stress and microbial virulence. Here we assess 'off-pump' coronary artery surgery on the beating heart for changes in plasma iron chemistry. Seventeen patients undergoing cardiac surgery using the 'Octopus' myocardial wall stabilisation device were monitored at five time points for changes in plasma iron chemistry. This group was further divided into those (n=9) who had one- or two- (n=8) vessel grafts, and compared with eight patients undergoing conventional coronary artery surgery. Patients undergoing beating heart surgery had significantly lower levels of total plasma non-haem iron, and a decreased percentage saturation of their transferrin at all time points compared to conventional bypass patients. Plasma iron overload occurred in only one patient undergoing CCPB. Beating heart surgery appears to decrease red blood cell haemolysis, and tissue damage during the operative procedures and thereby significantly decreases the risk of plasma iron overload associated with conventional bypass.

Off-pump coronary artery bypass. Mid-term results

OBJECTIVES

Off-pump coronary artery bypass grafting (CABG) on the beating heart has become popular procedure in cardiac surgery and its initial results appeared favorable. We report our early and mid-term results of off-pump CABG performed at Shin-Tokyo Hospital.

METHODS

Medical records of patients undergoing off-pump or conventional on-pump CABG from September 1, 1996, to August 31, 1999 were retrospectively reviewed. Patients underwent off-pump CABG were further classified into 2 groups; MIDCAB (Off-pump CABG for single vessel revascularization via a small skin incision) and OPCAB (off-pump CABG mainly approached via midline sternotomy) group. Their preoperative, perioperative, and follow-up data were collected and analyzed.

RESULTS

Among a total of 995 cases of CABG, 194 cases were off-pump CABG (male/female 142/52, mean age 66.9). The mean number of distal anastomoses in off-pump CABG was 1.9 +/- 0.9 (1.0 +/- 0.0 in MIDCAB and 2.3 +/- 0.7 in OPCAB), which was significantly fewer than in on-pump CABG (3.6 +/- 1.1), with p < 0.0001. Intubation time (5.3 +/- 5.7 hours in off-pump CABG vs 13.1 +/- 24.2 hours in on-pump CABG), ICU stay (1.7 +/- 1.1 vs 3.2 +/- 3.0 days), and postoperative hospital stay (14.0 +/- 7.9 vs 18.1 +/- 12.1 days) in off-pump CABG were significantly shorter than in on-pump CABG (p < 0.0001). In the off-pump CABG group, there were no in-hospital deaths and 14 major complications, fewer than in on-pump CABG (8 hospital deaths and 114 major complications). Postoperative angiography before hospital discharge was conducted in 80 patients (41.2%) and showed 2 occlusions, giving a graft patency rate of 98.6% in the off-pump group. During follow-up (0.9 +/- 0.6 year) period, there were 5 non-cardiac deaths and 20 cardiac events in the off-pump group. The actuarial survival rate at 36 months was 94.6% for off-pump CABG, showing no significant difference from the rate for conventional CABG patients (95.2% at 36 month, p = NS) The event-free rate was 84.0% at 36 months in off-pump CABG patients; however, which was less favorable than on-pump CABG patients (88.0% at 36 months, p < 0.05).

CONCLUSIONS

Both in-hospital and mid-term results for off-pump CABG patients were acceptable. Isolated CABG can thus be safely performed without cardiopulmonary bypass. Advances in coronary stabilization have contributed to these improved results. The observed long-term cardiac events may be related to incomplete revascularization.

Markers of myocardial ischemia after minimally invasive and conventional coronary operation

BACKGROUND

The purpose of this study was to evaluate the course of serum markers of myocardial tissue damage after two different types of minimally invasive coronary surgical procedures (MICS) as compared with conventional coronary artery bypass grafting (CABG).

METHODS

We enrolled 87 patients with one- or two-vessel disease scheduled for one of the three procedures: minimally invasive direct coronary artery bypass grafting (MIDCABG) by lateral thoracotomy (n = 29), the OCTOPUS method by median sternotomy (n = 27), and CABG (n = 31). Creatine kinase activity (CK), creatine kinase MB activity (CK-MB act), creatine kinase MB mass concentration (CK-MB mass), myoglobin concentration (MG), and cardiac troponin I concentration (cTnI) were measured perioperatively until the second postoperative day.

RESULTS

Creatine kinase-MB, CK-MB mass, and cTnI were significantly higher after CABG and were nearly maintained within the normal range in MICS. Creatine kinase and MG were significantly lower in the OCTOPUS group than in the MIDCABG or CABG groups.

CONCLUSIONS

Minimally invasive coronary surgical procedures cause less myocardial injury than CABG as indicated by specific serum markers. However, higher CK and MG reflect more substantial skeletal muscle trauma during MIDCABG operation compared with OCTOPUS procedures.

Anesthesia and Regional Anesthetic Techniques for Minimally Invasive Direct Coronary Artery Bypass Surgery

An innovative new approach to coronary revasculariza tion, minimally invasive direct coronary artery bypass is performed via a small anterior minithoracotomy or ministernotomy on a beating heart without the aid of cardiopulmonary bypass. Components of this tech nique, including thoracoscopic video-assisted harvest ing of the internal mammary artery, often with har monic scalpel and potentially even robotic assistance, necessitate prolonged one-lung ventilation. In the ab sence of cardioplegia, myocardial protection during normothermic beating heart surgery poses a challenge. Patient selection is important to avoid intraoperative and postoperative complications. Prolonged single- lung ventilation, incomplete revascularization in hybrid procedures, and limited access for rapid intervention pose challenges with patient management. Conversion to sternotomy may be required in 5% to 7% of patients, and extension of portals over several dermatomal seg ments mandate a versatile analgesic technique. Re gional anesthesia as analgesic adjuvant allows lighter levels of general anesthesia during surgery with mini mal intraoperative hemodynamic changes and a smooth transition to postoperative analgesia. Although a num ber of regional techniques may be used to achieve this goal, thoracic epidural analgesia or continuous percuta neous paravertebral block seem to offer specific advan tages of cardiac sympathectomy.

Surgical myocardial revascularization without cardiopulmonary bypass

BACKGROUND

Though coronary artery bypass grafting (CABG) without cardiopulmonary bypass is being performed with increasing frequency, in the absence of adequate angiographic follow-up, safety, reproducibility, and efficacy of the procedure remain doubtful. In this prospective study, we report the results obtained by 100% angiographic follow-up of 96 consecutive patients.

METHODS

A total of 96 patients (age range 33 to 76 years) underwent CABG without cardiopulmonary bypass. Single vessel disease was present in 46 (47.9%) patients, double vessel disease in 31 (32.3%), and triple vessel disease in 19 (19.8%) patients. All patients were operated through a standard midsternotomy and an optimal combination of pharmacological and mechanical methods were used to restrict cardiac movements during anastomosis. All patients underwent coronary angiography before discharge from the hospital.

RESULTS

A total of 160 grafts were placed (range 1 to 4 grafts per patient, average 1.7+/-0.3 grafts per patient). A single graft was placed in 46 patients, double grafts in 38, triple grafts in 10, and quadruple grafts in 2 patients. Various grafts included pedicled left internal mammary artery (LIMA) (n = 95), free LIMA (n = 1), right internal mammary artery (n = 14), radial artery (n = 24), right gastroepiploic artery (n = 5), and saphenous vein grafts (n = 21). Operative mortality was 1.0% (1 of 96). Two patients required reoperation for excessive bleeding. Mean hospital stay was 5.7+/-1.2 days. Overall angiographic patency was 95.0% with LIMA patency of 97.9% (93 of 95). One patient with block in midsegment of LIMA was reoperated using cardiopulmonary bypass. Follow-up ranged from 4 to 17 months (mean 8.2+/-3.1 months). Two patients (one with narrowed LIMA to left anterior descending artery anastomosis, and one with patent anastomosis) had residual angina.

CONCLUSIONS

Coronary artery bypass grafting without cardiopulmonary bypass is a reproducible, effective, and safe option in selected group of patients. A conscientious approach in patient selection and route of operation is required.

Evaluation of a new device for quick sutureless coronary artery anastomosis in surviving sheep

OBJECTIVE

A new device for performing quick sutureless vascular anastomosis by means of stent technology has recently been developed by Jomed International, Helsingborg, Sweden. The efficacy of this GraftConnector was studied in a sheep model.

METHODS

In adult sheep, a left anterior thoracotomy under the fourth rib extended across the sternum gave good access to the left anterior descending branch (LAD) and the right internal mammary artery (RIMA). On beating hearts, the GraftConnector group had the RIMA connected to the LAD by means of the new device, while the control animals had the same anastomoses sutured with continuous 7-0 polypropylene sutures. The time for completing the anastomosis (ischemic time) was recorded and the blood flow in the RIMA was recorded with the proximal LAD open and closed, respectively. An intra-operative fluoroscopy with contrast injection directly into the graft was done. Finally the proximal LAD was ligated. The surviving animals are to be followed up.

RESULTS

Seven (46%) of the 15 animals operated on with the traditional suturing technique and seven (63%) of the 11 GraftConnector sheep survived the procedures and are to be followed up. The 11 anastomoses done with the GraftConnector were completed in 2.41+/-0.2 min, and the 14 anastomoses sutured with continuous suture were completed in 6.93+/-0.419 min (P<0.0001). The RIMA blood-flows in the two groups were comparable and are presented. All the surviving animals had open anastomoses at fluoroscopy.

CONCLUSIONS

Quick coronary artery anastomoses without suturing on beating hearts can be completed with the new GraftConnector. The GraftConnector creates reproducible anastomoses in much less time than suturing, the per-operative mortality in the GraftConnector Group was accordingly lower. Long-time follow-up of the patency in surviving animals is pending. The presented device may ultimately permit quick anastomoses endoscopically.

Coronary artery bypass grafting in patient with malignant neoplasm. Efficacy of coronary artery bypass grafting on beating heart

OBJECTIVE

Coronary artery bypass grafting (CABG) prior to noncardiac major surgery has effectively decreases short- and long-term mortality related to coronary ischemia. Coronary artery bypass on the beating heart is conducted to avoid the risk of cardiopulmonary bypass and it has contribute to shorten recovery time.

METHODS

Subjects were 19 patients with malignant neoplasm for whom a retrospective chart review was made between Jan. 1, 1992 and July 31, 1998. In the early phase of this study, between Jan. 1, 1992, and Dec. 31, 1997, CABG was performed using cardiopulmonary bypass, and late phase, between Jan. 1, 1998, and July 1, 1998, CABG was done on the beating heart without cardiopulmonary bypass.

RESULTS

Conventional CABG was performed in 12 patients with neoplasms (10 male and 2 female, age 64.7 +/- 6.1 years), and CABG on the beating heart was performed in 7 patients (6 male and 1 female, age 68.0 +/- 7.5 years). Fewer number of bypass grafts were made in the beating-heart CABG group (1.3 +/- 0.5 in beating-heart CABG versus 3.9 +/- 1.1 in conventional CABG). No cardiac events occurred in either group during the surgery for malignant tumors. The operative interval between CABG and cancer surgery was significantly shorter in the beating-heart CABG group (21.8 +/- 17.9 days in beating-heart CABG versus 53.5 +/- 42.9 days in conventional CABG, p < 0.05).

CONCLUSION

Patients with severe coronary artery disease and malignant neoplasms should undergo coronary artery revascularization before the neoplasm is treated. CABG on the beating-heart was safe and effective procedure in those with malignant neoplasms.

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.

Multivessel coronary artery bypass surgery without cardiopulmonary bypass

BACKGROUND

There is limited experience with complete myocardial revascularization on a beating heart. Using a mechanical stabilization system, we sought to determine if complete coronary revascularization is feasible without cardiopulmonary bypass and what the short-term clinical outcome would be.

METHODS

From February through September 1998, 26 patients underwent complete myocardial revascularization with Medtronics Octopus Tissue Stabilization System. Mean age for the group was 62 +/- 7 years (range 48 to 78 years); 11% had prior interventions. Mean preoperative ejection fraction was 49% +/- 14% (range 20% to 66%); 38% of operations were performed urgently. The mean number of vessels grafted was 3.0 +/- 0.9 (range 1 to 5 grafts/patient). In 96% of patients, at least one arterial graft was used. Fifteen percent of patients had 2 or more arterial grafts. In 58% of patients, a branch of circumflex coronary artery was bypassed.

RESULTS

The median time to extubation was 2 hours (range 0 to 37 hours). None of the patients had perioperative myocardial infarction, cerebrovascular accident, or renal failure requiring dialysis. The 30-day survival rate was 100%. Angiographic follow-up was not available. At a mean follow-up period of 3.8 +/- 2.9 months, all patients remained free of angina and none has required cardiac reintervention.

CONCLUSIONS

Complete myocardial revascularization on a beating heart can be achieved with the currently available stabilization systems and is associated with low perioperative complications and satisfactory short-term clinical outcomes. The long-term outcomes and graft patency remain to be determined.

Integrated left anterior small thoracotomy and angioplasty for coronary artery revascularization

BACKGROUND

The minimal access surgical technique of a left anterior small thoracotomy (LAST) for coronary artery bypass grafting is now well established. This procedure however, does not allow multivessel revascularization. We present our early experience of an integrated approach using LAST and percutaneous transluminal coronary angioplasty (PTCA), either staged or simultaneous.

METHODS

Eighteen patients (14 men and 4 women), mean age 63 (range 35-87 years) were treated. Four patients underwent simultaneous LAST and PTCA revascularization. The remaining 14 patients were first treated with the LAST procedure, followed 1-3 days later by angioplasty. Angiographic assessment was carried out before PTCA and at 6 months after.

RESULTS

The 14 patients who underwent the staged procedure all had patent left internal mammary artery/left anterior descending coronary artery grafts. Angioplasty was performed on 21 vessels (10 stented) with good early angiographic results. All patients were extubated early, mean intensive care stay was 14.7 + 9.4 hours, mean hospital stay was 5 + 1.5 days. All patients were symptom free at 18 months follow-up.

CONCLUSIONS

Staged LAST and angioplasty is a safe and effective approach suitable for patients in whom there are contraindications to the use of extracorporeal circulation. The simultaneous approach is limited by the risk of bleeding associated with the use of anticoagulation when coronary stenting is required.

The elephant trunk operation in complex aortic disease

Extensive aneurysmal disease of the aorta presents considerable challenges to the cardiovascular surgeon and is generally treated with a staged approach. The elephant trunk principle, in which the downstream end of the primarily inserted graft is allowed to float freely in the downstream aorta, serves this approach. This principle greatly facilitates subsequent operation(s) and shortens the period of distal aortic occlusion. This review describes the state of the art of this technique, its various uses, and the results obtained.

Uniform safety of beating heart surgery using the octopus tissue stabilization system

BACKGROUND AND PURPOSE

Minimally invasive coronary artery bypass grafting (CABG) has been facilitated by the introduction of the Octopus Tissue Stabilization system (OTS). OTS improves exposure immobilizing the heart with minimal hemodynamic effects allowing multivessels off cardiopulmonary bypass (CPB) CABG. The purpose of this study was to compare the utilization and clinical outcome of the OTS in three geographically distinct centers.

METHODS

239 patients who underwent OTS-CABG at Allegheny University Hospital/Medical College of Pennsylvania, Harrisburg Hospital, and Park Nicollet Clinic/HealthSystem Minnesota were reviewed. Age, acuity of patients, and number and type of vessels bypassed were recorded. Complications, mortality, length of hospital stay, incidence of conversion to CPB and blood transfusions, and operating room costs were compared to risk matched control patients who underwent CPB CABG during the same period.

RESULTS

Results were similar in all three centers. The average age was 62.3 years. Emergent operation was necessary in 7%-10% of patients, the operations averaged 1.8 grafts/patient. Arteries bypassed were LAD, DIAG, OM, RCA, PDA, and RPLB. There were 96% of operations completed without CPB. Morbidity was low (12%). Atrial fibrillation and blood transfusion rate were decreased. Mortality was 0 compared with a predicted mortality of 1.6%. Hospital length of stay was shorter and operating room costs were 61% lower.

CONCLUSIONS

OTS provides predictable reproducible immobilization allowing the performance of single and multiple off-pump CABG to almost all coronary branches with minimal morbidity and decreased costs in a variety of patients. Similar findings from three different centers suggests that these results are easily reproducible.

Anesthetic management of patients undergoing coronary artery bypass grafting with the use of an axial flow pump and a short-acting beta-blocker

OBJECTIVES

To describe the clinical protocol regarding monitoring, pharmacologic interventions, and postoperative care during and after coronary artery bypass grafting (CABG) on the beating heart with an axial flow pump and a short-acting beta-blocker.

DESIGN

A retrospective study.

SETTING

A university hospital.

PARTICIPANTS

Seventeen patients scheduled for elective CABG.

INTERVENTIONS

Invasive monitoring was performed with either a standard pulmonary artery catheter (PAC) or a surgically placed PAC. An axial flow pump was inserted through a graft sutured to the ascending aorta. A short-acting beta-blocker was administered to decrease the motion of the heart and make conditions for CABG adequate and safe.

MEASUREMENTS AND MAIN RESULTS

Compared with baseline measurements, there were significant decreases in mean arterial blood pressure, mixed venous oxygen saturation, and right ventricular ejection fraction during maximal axial flow pump support and beta-blockade. No significant change in heart rate was observed at this time. Hemodynamic variables were normalized in the intensive care unit. All patients were separated from the Hemopump without inotropic support, and values of troponin-T, aspartate aminotransferase, and alanine aminotransferase were low postoperatively. All patients survived and were discharged from the hospital.

CONCLUSION

The anesthetic protocol for patients undergoing surgery with a beating heart and the combined use of an axial flow pump and a short-acting beta-blocker is outlined. Multiple-vessel CABG on the beating heart was performed with maintenance of an acceptable hemodynamic situation.

[Minimally invasive cardiac surgery: surgical techniques and anesthetic problems]

OBJECTIVE

To review current data on minimally invasive cardiac surgery.

DATA SOURCES

Search through the Medline data base of French or English articles.

DATA EXTRACTION

The articles were analysed to make a synthesis of the various techniques with their main indications and contra-indications.

DATA SYNTHESIS

Minimally invasive cardiac surgery includes various surgical procedures. The usual techniques are described, their major benefits and drawbacks are discussed. The main goals of anaesthetic management are preservation of ventricular function and systemic perfusion, detection and treatment of myocardial ischaemia, prevention of hypothermia in case of coronary artery bypass grafting on the beating heart via sternotomy, intermittent selective ventilation of the collapsed lung using CPAP in case of limited thoracotomy. Expertise in transoesophageal echocardiography is essential for insertion and checking the accurate positioning of the various catheters of the endovascular CPB Heartport system (pulmonary vent, endosinus catheter, venous cannula, endoaortic clamp) allowing coronary artery bypass grafting and mitral valve surgery through limited thoracotomy and finally, detection of retained intracardiac air and assessment of complete clearing of cardiac cavities after mitral valve surgery through limited thoracotomy and aortic valve surgery via ministernotomy. Short-acting anaesthetic agents allow rapid recovery from anaesthesia, early extubation and discharge to the surgical ward within 24 h, whereas overall time spent in the operating room is often longer than with conventional cardiac surgery.

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.

Coronary artery bypass graft after esophagogastrectomy

A 71-year-old male with a history of retrosternal gastric bypass, after a resected esophageal carcinoma, developed angina pectoris due to stenosis of the left main trunk and the left anterior descending artery. The patient was treated with off-pump beating-heart coronary artery bypass approached via left thoracotomy. Two free conduits arising from the left internal mammary artery were utilized for this particular case, since the aortocoronary bypass was impossible due to the severely calcified aorta. Postoperative angiography confirmed good coronary flow and the patient has been symptom free for 6 months.

Patient outcome as a selection criterion in determining treatment mode

The climate of health care reform encourages scrutiny of traditional and new forms of medical and surgical therapy. With the emergence of technologically innovative cardiac procedures, therapy advocates must weigh cost versus patient outcomes. Therapies range from purely medical management, through staged interventions, to median sternotomy and cardiopulmonary bypass. Outcomes will necessarily be related to quality of life. A literature search was performed to determine types of medical and surgical therapies associated with patient outcomes as they define quality of life. Medical treatment may include the use of anti-platelet therapy, beta-blockers and diuretics to treat the cardiac patient at low risk who can maintain an acceptable quality of life. Improvements in medical therapies may extend the life of the low-risk patient, eliminating the need to consider bypass surgery. Some patients at high risk, or with left ventricular hypertrophy combined with an impaired ejection fraction, may require coronary artery bypass surgery. Studies indicate that patients undergoing open heart surgery demonstrate significant improvement in functional classification, increased activity and reduction in anti-anginal medications. Proponents of minimally invasive surgery claim potential benefits of lower surgical trauma, shorter hospital stays and shorter recovery times. Quality of life is defined by outcomes. Only by comparing outcomes of all available therapies can a physician or patient make an informed decision regarding treatment.

Intraoperative cardiac troponin T release and lactate metabolism during coronary artery surgery: comparison of beating heart with conventional coronary artery surgery with cardiopulmonary bypass

OBJECTIVE

To compare cardiac troponin T release and lactate metabolism in coronary sinus and arterial blood during uncomplicated coronary grafting on the beating heart with conventional coronary grafting using cardiopulmonary bypass.

DESIGN

A prospective observational study with simultaneous sampling of coronary sinus and arterial blood: before and 1, 4, 10, and 20 minutes after reperfusion for analysis of cardiac troponin T and lactate. Cardiac troponin T was also analysed in venous samples taken 3, 6, 24, 48, and 72 hours after surgery.

SETTING

Cardiac surgical unit in a tertiary referral centre.

PATIENTS

18 patients undergoing coronary grafting on the beating heart (10 single vessel and eight two-vessel grafting) and eight undergoing two-vessel grafting with cardiopulmonary bypass.

RESULTS

Cardiac troponin T was detected in coronary sinus blood in all patients by 20 minutes after beating heart coronary artery surgery before arterial concentrations were consistently increased. Peak arterial and coronary sinus cardiac troponin T values on the beating heart during single (0.03 (0 to 0. 05) and 0.09 (0.07 to 0.16 microg/l, respectively) and two-vessel grafting (0.1 (0.07 to 0.11) and 0.19 (0.14 to 0.25) microg/l) were lower than the values obtained during cardiopulmonary bypass (0.64 (0.52 to 0.72) and 1.4 (0.9 to 2.0) microg/l) (p < 0.05). The area under the curve of venous cardiac troponin T over 72 hours for two-vessel grafting on the beating heart was less than with cardiopulmonary bypass (13 (10 to 16) v 68 (26 to 102) microg.h/l) (p < 0.001). Lactate extraction began within one minute of snare release during beating heart coronary surgery while lactate was still being produced 20 minutes after cross clamp release following cardiopulmonary bypass.

CONCLUSIONS

Lower intraoperative and serial venous cardiac troponin T concentrations suggest a lesser degree of myocyte injury during beating heart coronary artery surgery than during cardiopulmonary bypass. Oxidative metabolism also recovers more rapidly with beating heart coronary artery surgery than with conventional coronary grafting. Coronary sinus cardiac troponin T concentrations increased earlier and were greater than arterial concentrations during beating heart surgery, suggesting that this may be a more sensitive method of intraoperative assessment of myocardial injury.

Effect of coronary occlusion on left ventricular function with and without collateral supply during beating heart coronary artery surgery

OBJECTIVE

To study the effects of coronary occlusion and collateral supply on left ventricular (LV) function during beating heart coronary artery surgery.

DESIGN

Prospective intraoperative study, performed at baseline, during wall stabilisation, coronary artery occlusion, and 2 and 10 minutes after reperfusion. Transoesophageal M mode echocardiograms, simultaneous high fidelity LV pressure, and thermodilution cardiac output were measured. LV anterior wall thickening, thinning velocities, thickening fraction, regional work, and power production were derived. Asynchrony during the isovolumic periods was quantified as cycle efficiency.

SETTING

Tertiary referral cardiac centre.

PATIENTS

14 patients with stable angina, mean (SD) age 62 (7) years, undergoing left anterior descending artery grafting using the "Octopus" device.

RESULTS

Collaterals were absent in nine patients and present in five. Epicardial stabilisation did not affect LV function. Results are expressed as mean (SD). Coronary occlusion (15.6 (2) minutes) depressed anterior wall thickening (1.4 (0.6) v 2.6 (0.6) cm/s) and thinning velocities (1.4 (0.5) v 3.0 (0.6) cm/s), regional work (2.2 (0.8) v 4.6 (0.6) mJ/cm2), and power (21 (4) v 33 (5) mW/cm2) in patients without collaterals (p < 0.05 for all), but only wall thinning (3.5 (0.5) v 4.8 (0.5) cm/s, p < 0.05) in patients with collaterals. All returned to baseline within 10 minutes of reperfusion. Cycle efficiency and regional work were impaired at baseline and fell during occlusion, regardless of collaterals. Within 10 minutes of reperfusion both had increased above baseline.

CONCLUSIONS

Coronary occlusion for up to 15 minutes during beating heart coronary artery surgery depressed standard measurements of systolic and diastolic anterior wall function in patients without collaterals, but only those of diastolic function in patients with collaterals. Regional synchrony decreased in both groups. All disturbances regressed within 10 minutes of reperfusion.

No-Touch Method for Off-Pump Coronary Artery Bypass Grafting

We describe a simple no-touch method of coronary artery bypass grafting that facilitates anastomosis on the beating heart by means of a blower. This technique avoids clamping or occluding the target coronary artery. We successfully performed 22 distal anastomoses in 12 direct off-pump coronary artery bypass operations with no in-hospital mortality or cardiac complications. Two patients underwent a left anterolateral small thoracotomy for single-vessel disease and 10 had a median sternotomy for double-vessel disease. The technique provided a dry operative field and adequate exposure at the moment of suture.

Controlled intermittent asystole: pharmacologic potentiation of vagal-induced asystole

BACKGROUND

Minimally invasive direct coronary artery bypass graft operations have, to date, displayed a higher rate of early graft failure than conventional coronary artery bypass procedures using extracorporeal technology. Construction of the coronary artery anastomosis on a beating heart versus a quiescent heart is likely an important factor in this difference between the two approaches. Controlled intermittent asystole induced by vagal stimulation to give transient nonchemically induced asystole for brief intervals sufficient for placement of coronary artery sutures might improve the precision of minimally invasive direct coronary artery bypass graft anastomoses and reduce graft failure while increasing the technical ease of operation.

METHODS

The feasibility of producing transient, reversible asystole with combined vagus nerve stimulation and treatment with a pharmacologic regimen of (1) an acetylcholinesterase inhibitor (pyridostigmine, 0.5 mg/kg), (2) a beta-adrenergic receptor blocker (propranolol, 80 microg/kg), and (3) a calcium-channel blocker (verapamil, 50 microg/kg) was studied in a sheep model. Seven animals underwent right vagus nerve stimulation in two modes: (1) a single continuous 60-second impulse and (2) multiple sequential 15-second impulses.

RESULTS

Vagal stimulation alone achieved bradycardia without consistent and reproducible cardiac arrest. After drug administration 6 animals displayed significant potentiation of vagal-induced asystole in the 60-second stimulation protocol (1.6+/-0.9 seconds non-drug-treated versus 52.0+/-5.6 seconds drug-treated; p < 0.05). In the sequential 15-second impulse protocol after drug treatment, 6 animals achieved consistent, escape-free asystole during five to six sequential 15-second stimulations versus a brief pause and bradycardia produced without drug treatment.

CONCLUSIONS

Increased acetylcholine activity by acetylcholinesterase inhibition and prevention of electromechanical escape activity by beta-adrenergic receptor and calcium-channel blockade during vagal stimulation produced a marked potentiation of vagal-induced asystole and a means of achieving controlled intermittent asystole. Controlled intermittent asystole achieved by pharmacologic potentiation of vagal-induced asystole may be a useful technique for enhancing technical ease in minimally invasive direct coronary artery bypass graft operations.

Robotically assisted microsurgery for endoscopic coronary artery bypass grafting

BACKGROUND

As minimally invasive approaches to cardiac surgery have expanded, a significant number of limitations have become apparent, particularly the lack of adequate precision with standard endoscopic instruments. We hypothesized that the use of robotics would eliminate some of these limitations.

METHODS

Twenty-five coronary anastomoses on an isolated porcine heart, using an arterial conduit to the left anterior descending artery, were performed endoscopically with a microsurgical robotic system. Sophisticated robotic engineering was used to control modified endoscopic instruments under direct surgeon control. Computer tremor elimination and motion scaling allowed for precise maneuvering. An arteriotomy was placed in the left anterior descending artery, and an arterial conduit was positioned for anastomosis. The camera and port sites were placed 90 degrees from the long axis of the arteriotomy. A 7-0 Prolene (Ethicon, Somerville, NJ) suture was used to perform the anastomosis in a continuous fashion, begun at the 12 o'clock position and continued counterclockwise. After completion of half of the anastomosis, the conduits were pulled down and the final sutures were placed. The sutures were tied intracorporeally and the procedure was completed.

RESULTS

The 25 conduits were successfully completed and showed good probe patency. Average time for completion of the anastomosis was 31.7 +/- 2.0 minutes. Appropriate port placement and orientation, and stabilization of the conduits were critical. The lack of tremor and motion scaling allowed for the precise movements needed to complete an endoscopic microvascular anastomosis.

CONCLUSIONS

Coronary artery anastomoses are technically feasible with use of robotic instrumentation. This technology may enable the development of a truly endoscopic approach to bypass surgery.

Minimally invasive direct coronary artery bypass surgery

Traditional coronary artery bypass surgery involves a median sternotomy and the use of a heart-lung machine to stabilize the heart during suturing. Minimally invasive coronary artery surgery employs small incisions directly over the target vessels and avoids the use of a heart-lung machine, which can cause postoperative complications. The target coronary vessels are stabilized in alternative ways, potentially hazardous manipulation of the ascending aorta is avoided, and the subclavian and axillary arteries provide alternative inflow sources. Other new techniques used in minimally invasive procedures include a coronary artery cannula to avoid intraoperative ischemia and wound irrigation catheters to administer postoperative bupivacaine hydrochloride. Perioperative nurses need to become familiar with these new techniques to be able to plan and implement effective patient care.