MIDCAB Research Articles

Endoscope-Assisted Minimally Invasive Surgery for Coronary Artery Bypass

Objective: Cardiac surgeons began in this decade to apply the endoscopes in their practices. Endoscopic graft harvest for coronary artery bypass surgery (CABG) has become the routine practice in many institutes. However, endoscopic harvest of the left internal mammary artery (LIMA) has remained a technical challenge. Methods: From April 2002 to April 2004, 40 patients underwent minimally invasive direct CABG using LIMA to left anterior descending (LAD) artery bypass. Twentyone of them had endoscopic harvest of LIMA. Results: There was neither early nor late operative mortality. Endoscopic LIMA harvest time ranged from 38 to 125 minutes (mean 56 minutes). All harvested LIMAs had a burst flow while being cut from the distal end. The length of thoracotomy was 5 to 8 cm (mean 6.2 cm).Ten patients were extubated immediately. One patient had hemothorax which required chest tube insertion. The intensive care unit (ICU) ventilation time was 0 to 40 hours (mean 7 hours). The ICU stay and hospital stay were 1.3±0.3 and 6.2±1.5 days, respectively. Conclusions: Endoscope-assisted LIMA harvest is a feasible technique. The learning curve, however, shows that this approach reduces wound length, recovery time, and helps extend the graft length to facilitate the anastomosis. It provides patients with an alternative choice to have a satisfactory conduit in a minimally invasive way.

Non-anastomotic avulsion of a left internal mammary artery graft - a rare complication of minimally invasive direct coronary artery bypass surgery

To describe a rare complication of minimally invasive coronary artery bypass surgery. Case report. We present a 72-year-old patient with a left anterior descending artery stenosis who underwent elective minimally invasive direct coronary artery bypass (MIDCAB) surgery. Three months post-operatively he developed an anterior chest wall haematoma with electrocardiographic and enzyme evidence of myocardial ischaemia, though without haemodynamic embarrassment. Surgical exploration revealed non-anastomotic avulsion of the LIMA graft, which was bleeding freely into the left hemithorax. Minimally invasive direct coronary artery bypass surgery is now widely practised. Post-operative interruption of the left internal mammary artery graft is uncommon and avulsion of the graft proximal to the anastomosis with the left anterior descending artery has only been described in the literature on three occasions. This complication has been reported once in the setting of conventional bypass surgery and twice in the setting of minimally invasive direct coronary artery bypass surgery. In all of these cases, abrupt graft failure resulted in significant haemodynamic and/or ischaemic compromise, and all occurred within two weeks of surgery. Clinicians should be reminded of this rare though potentially catastrophic complication of MIDCAB surgery.

Quality of life and coping following minimally invasive direct coronary artery bypass (MIDCAB) surgery.

Minimally invasive direct coronary artery bypass (MIDCAB) surgery has been shown to be a promising technique for surgical treatment of single or double vessel disease. However, little is known about quality of life, mood state or coping in this group of patients. The records of 55 consecutive patients who underwent MIDCAB surgery at Harefield Hospital between April 1999 and May 2001 were reviewed. In order to assess quality of life, mood state and coping, patients were contacted by telephone to conduct a semi-structured interview and were subsequently sent four questionnaires. The measures used were the Hospital Anxiety and Depression Scale, the Short Form Health Survey, the WHOQoL-BREF and the COPE. Forty-eight patients were contacted by telephone, forty-four of whom returned the completed questionnaires. Overall ratings of quality of life were excellent for the majority of patients, and rates of anxiety and depression were lower than previously found following coronary artery bypass surgery. It is concluded that following MIDCAB surgery quality of life and mood state outcomes are encouraging. However, a prospective, longitudinal study is now required to further elucidate the relationship between quality of life, mood state and coping and to identify predictive factors for physical and psychological outcome following this new surgical technique.

Percutaneous coronary intervention with drug-eluting stent implantation vs. minimally invasive direct coronary artery bypass (MIDCAB) in patients with left anterior descending coronary artery stenosis

The aim of this study was to assess the effects of percutaneous coronary intervention with drug-eluting stents (DESs) versus minimally invasive direct coronary artery bypass (MIDCAB) surgery in the management of patients with proximal left anterior descending (LAD) coronary artery stenosis. Until recent years, despite the advantages of percutaneous transluminal coronary angioplasty (PTCA) with bare metal stent implantation, such as shorter hospital stays and recovery time, MIDCAB showed better results with regard to the need for repeated intervention in the target vessel than PTCA with proximal LAD lesions. Symptomatic patients (n = 189) were randomly assigned to DES group (n = 119) and MIDCAB group (n = 70). Patients with an isolated high-grade lesion (stenosis of > or = 70% of the luminal diameter) in the proximal LAD coronary artery (from the ostium to the first diagonal branch) were included in this study. During the 6-month follow-up period, 1.7% (n = 2) in the DES group needed repeated revascularization procedures for target lesion revascularization compared with 5.9% (n = 4) in the MIDCAB group (P = 0.196). The rates of death and myocardial infarction were similar in both groups [DES 0.0% (n = 0) vs. MIDCAB 2.9% (n = 2), P = 0.135; DES 1.7% (n = 2) vs. MIDCAB 2.9% (n = 2), P = 0.627; respectively] during 6 months of follow-up. In-hospital length of stay was significantly shorter in the DES group compared with the MIDCAB group (5.8 +/- 2.1 days vs. 8.9 +/- 2.6 days; P = 0.001). DES implantation and MIDCAB surgery showed similar rates of myocardial infarction, the need for repeated revascularization, and death during 6 months of follow-up. However, DES implantation resulted in lower average number of hospital stays and similar postoperative complications.

Comparison of continuous, stat, and intermittent cardiac output measurements in patients undergoing minimally invasive direct coronary artery bypass surgery

Objective: To compare intermittent cardiac output (ICO) with continuous cardiac output (CCO) and stat cardiac output (SCO) measurements in patients undergoing minimally invasive direct coronary artery bypass (MIDCAB) surgery. Design: Prospective, clinical study. Setting: Single, tertiary referral center. Participants: Twenty adult patients undergoing off-pump MIDCAB surgery from January through June 2000. Interventions: Each patient had a 7.5F 5-lumen pulmonary artery thermodilution catheter (CCO catheter, Baxter Healthcare Corporation, Irvine, CA) inserted for measurement of cardiac output (CO). ICO, CCO, and SCO were compared at 10 predefined time points. Results: A total of 400 data pairs for CO were obtained. ICO values ranged from 1.8 to 8.4 L/min; CCO, 1.9 to 7.5 L/min; and SCO, 2.25 to 6.35 L/min. Correlation between ICO and CCO was significant (correlation coefficient, r = 0.78, p < 0.001), accompanied by a bias of −0.095 L/min and precision of 0.729 L/min. Similarly, the correlation between ICO and SCO was significant (r = 0.79, p < 0.001), accompanied by good accuracy (bias, 0.084 L/min) and precision (0.843 L/min). There were statistically significant decreases in mean arterial pressure, CO, cardiac index, stroke volume, stroke volume index, and left and right ventricular stroke work indices during anastomosis of the left internal mammary artery to left anterior descending artery. These parameters returned to baseline preinduction values 1 minute after completion of the anastomosis. Conclusion: Excellent correlation, accuracy, and precision were found among the 3 methods of measuring CO in patients undergoing MIDCAB surgery. Further studies are needed to assess their accuracy in multivessel off-pump coronary artery bypass graft surgery and in patients with poor left ventricular function.

To ventilate or not after minimally invasive direct coronary artery bypass surgery: The role of epidural anesthesia

Objective: To evaluate the effect of immediate postoperative extubation and postoperative ventilation after minimally invasive direct coronary artery bypass (MIDCAB) surgery and to assess the role of epidural anesthesia. Design: Randomized prospective study. Setting: University hospital, single institution. Participants: Patients (n = 90) scheduled for elective MIDCAB surgery. Interventions: Patients were divided into 3 groups: 30 patients had general anesthesia and were extubated immediately after surgery (extubated group), 30 patients had a thoracic epidural and general anesthesia and were extubated immediately after surgery (epidural group), and 30 patients had general anesthesia and were ventilated after surgery (intubated group). Measurements and Main Results: With a similar cardiac index and less vasoactive medication, mean arterial blood pressure (77 ± 8 mmHg [mean ± SD]) and heart rate (76 ± 10 beats/min) in the epidural group were lower on the first postoperative day than in the intubated group (83 ± 10 mmHg and 81 ± 13 beats/min) and the extubated group (86 ± 10 mmHg and 83±13) (p = 0.01 and p = 0.09). Oxygenation on the first postoperative day was better in the epidural group than in the intubated group (14.8 ± 3.8 kPa v 12.6 ± 3.2 kPa; p = 0.05). The epidural group and the extubated group had a transient respiratory acidosis postoperatively. Pain score in the epidural group was lower on the first postoperative day than in the extubated group with general anesthesia (3.0 ± 1.6 visual analog scale v 4.6 ± 1.8 visual analog scale; p = 0.01). Hospital stay was shorter in the epidural group than in the ventilated group (5.9 ± 2.4 days v 8.1 ± 5.3 days; p = 0.05) Conclusion: Immediate postoperative extubation in patients with thoracic epidural anesthesia and supplemental general anesthesia provides the most favorable clinical circumstances after MIDCAB surgery. Copyright 2002, Elsevier Science (USA). All rights reserved.

Comparison of continuous thoracic epidural and paravertebral blocks for postoperative analgesia after minimally invasive direct coronary artery bypass surgery

Objective: To compare continuous thoracic epidural analgesia (TEA) and paravertebral block (PVB) for postoperative analgesia in patients undergoing minimally invasive direct coronary artery bypass (MIDCAB) surgery for quality of analgesia, complications, compliance to chest physiotherapy, hemodynamics, and respiratory effects. Design: Prospective, randomized study. Setting: Specialty research hospital. Participants: Forty-one consenting patients undergoing MIDCAB surgery. Interventions: Patients in the TEA group had an epidural catheter inserted at the T4-5 interspace, whereas patients in the PVB group had a catheter inserted in the paravertebral space on the left side at the T4-5 level. Measurements and Main Results: Parameters evaluated included visual analog scale pain scores at rest and while coughing, supplemental analgesic requirement, complications, hemodynamics, and respiratory parameters. Measurements were made at 2-hour intervals for 12 hours beginning at 10 minutes after endotracheal extubation. There was no statistically significant difference in visual analog scale scores and requirement of supplemental analgesia between the 2 groups. Cardiac index at 4 hours and 6 hours was significantly higher in the TEA group. Patients in the PVB group had significantly lower respiratory rates at 8, 10, and 12 hours. All other parameters were comparable. In 1 patient, the epidural space could not be catheterized. One patient in the TEA group had transient hypotension, and 1 patient complained of backache at the site of the epidural catheter insertion. Conclusion: PVB is as effective as TEA for postoperative analgesia after MIDCAB surgery. PVB is technically easier than TEA and may be safer than TEA because no complications were seen in the PVB group. Copyright © 2001 by W.B. Saunders Company

Haemodynamic Changes during Minimally Invasive Coronary Artery Bypass Surgery Using High-Dose Esmolol

We aimed to investigate the effects of high-dose esmolol on haemodynamics and oxygen extraction in minimally invasive direct coronary artery bypass (MIDCAB) surgery patients. Methods: In 18 patients, heart rate (HR), mean arterial (MAP), central venous (CVP), pulmonary capillary wedge pressure (PCWP), cardiac output (CO), and mixed venous oxygen saturation (SvO2) were prospectively measured after induction of anaesthesia (T1), start of surgery (T2), during bypass grafting with β-blockade (T3), and at the end of surgery (T4). Results: Mean esmolol dose at T3 was 0.44 ± 0.2 mg kg−1 min−1. HR was unchanged, whereas significant decreases in mean CO (3.1 ± 0.8 vs 4.8 ± 1.0 l min−1 m−2 pre-esmolol), MAP (53 ± 10 vs 89 ± 14 mmHg), and SvO2 (65 ± 10 vs 81 ± 4%) were observed during esmolol administration. All haemodynamic parameters normalized immediately after termination of esmolol (T4). Conclusions: Despite unchanged HR esmolol reduced CO and MAP suggesting a favorable reduction of myocardial oxygen consumption. Mean SvO2 during esmolol administration reflects an acceptable ratio of whole-body oxygen delivery and consumption. Haemodynamic changes with high-dose esmolol during MIDCAB surgery remain within safety margins.

Haemodynamic changes during minimally invasive coronary artery bypass surgery using high-dose esmolol

We aimed to investigate the effects of high-dose esmolol on haemodynamics and oxygen extraction in minimally invasive direct coronary artery bypass (MIDCAB) surgery patients. Methods: In 18 patients, heart rate (HR), mean arterial (MAP), central venous (CVP), pulmonary capillary wedge pressure (PCWP), cardiac output (CO), and mixed venous oxygen saturation (Sv0 2) were prospectively measured after induction of anaesthesia (T1), start of surgery (T2), during bypass grafting with β-blockade (T3), and at the end of surgery (T4). Results: Mean esmolol dose at T3 was 0.44±0.2 mg kg −1 min −1. HR was unchanged, whereas significant decreases in mean CO (3.1±0.8 vs 4.8±1.0 l min −1 m −2, pre-esmolol), MAP (53±10 vs 89±14 mmHg), and SvO 2 (65±10 vs 81±4%) were observed during esmolol administration. All haemodynamic parameters normalized immediately after termination of esmolol (T4). Conclusions: Despite unchanged HR esmolol reduced CO and MAP suggesting a favorable reduction of myocardial oxygen consumption. Mean Sv0 2 during esmolol administration reflects an acceptable ratio of whole-body oxygen delivery and consumption. Haemodynamic changes with high-dose esmolol during MIDCAB surgery remain within safety margins.

MIDCAB

MIDCAB

A comparative evaluation of intrapleural and thoracic epidural analgesia for postoperative pain relief after minimally invasive direct coronary artery bypass surgery

Objective: To compare the efficacy of thoracic epidural analgesia (TEA) and intrapleural analgesia (IPA) after minimally invasive direct coronary artery bypass (MIDCAB) surgery with regard to quality of analgesia and complications. Design: A prospective, randomized study. Setting: A specialty research hospital. Participants: Fifty consenting adults scheduled for MIDCAB surgery. Interventions: All patients underwent elective MIDCAB surgery. Patients in the TEA group (n = 25) had an epidural catheter inserted in the fourth to fifth thoracic interspace and those in the IPA group (n = 25) had an intrapleural catheter inserted in the sixth to seventh intercostal space intraoperatively under vision. Measurements and Main Results: Parameters evaluated after administration of bupivacaine (8 mL of 0.25% in the TEA group and 20 mL of 0.25% in the IPA group) on first demand included visual analog scale (VAS) pain scores, cardiovascular and respiratory (clinical, blood gases) function, wakefulness, supplemental analgesic requirement, and complications. Measurements were made at 2-hour intervals for the next 12 hours. VAS scores were significantly lower at 2, 6, 8, and 12 hours in the IPA group (TEA = 3.5, 4.5, 4.9, 4.6; IPA = 2.2, 3.6, 3.5, 3.7). There were no significant differences in hemodynamic or respiratory parameters or postoperative requirement for supplemental analgesia. In the TEA group, three patients had catheter migration and four had severe backache. Conclusion: IPA is a safe and effective technique for postoperative analgesia after MIDCAB surgery and has a low complication rate compared with TEA. Careful positioning, chest tube clamping, and anchoring of the catheter are mandatory for IPA to be effective.

Temporary Coronary Artery Perfusion Catheter During Minimally Invasive Coronary Surgery: Alan Coulson, MD, PhD, FCCP; Shahroukh Bakhshay, MD, FCCP; Judy Quarnstrom, LVN; and Phillip Spohn, BS

The purpose of this study was to investigate the use of an intracoronary cannula during minimally invasive direct coronary artery bypass (MIDCAB) surgery. Evaluation of the coronary perfusion catheter was conducted during MIDCAB surgery to determine if there was any trauma to the coronary artery. The study was retrospective with 45% follow-up arteriograms. A community hospital provided the setting for the study. Twenty patients undergoing MIDCAB surgery were included. Insertion of an intracoronary cannula was performed during MIDCAB surgery. Measurements were determined on 45% follow-up arteriograms, and clinical follow-up was done on patient status. The use of an intracoronary cannula during MIDCAB surgery did not result in any trauma to the cannulated coronary artery. The cannula prevented ischemia of the service area of the target coronary artery. ECG changes were avoided as were hypotension and arrhythmias. The cannula also helped stabilize the target coronary area during suturing.