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Innovations: Technology & Techniques in Cardiothoracic & Vascular Surgery:
doi: 10.1097/IMI.0000000000000035
Original Articles

Minimally Invasive Coronary Bypass Using Internal Thoracic Arteries via a Left Minithoracotomy: “The Nambiar Technique”

Nambiar, Pradeep FRCSC*†; Mittal, Chandermohan MCh*

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Author Information

From the *Max Superspeciality Hospital, New Delhi, India; and †Rockland Hospitals, New Delhi, India.

Accepted for publication October 24, 2013.

A video clip is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site ( www.innovjournal.com). Please use Firefox when accessing this file.

Presented at the Annual Scientific Meeting of the International Society for Minimally Invasive Cardiothoracic Surgery, May 30 – June 2, 2012, Los Angeles, CA USA.

Disclosure: The authors declare no conflicts of interest.

Address correspondence and reprint requests to Pradeep Nambiar, FRCSC, A3/1202, Uniworld City, Gurgaon 122002, Haryana, India. E-mail: namb1@hotmail.com.

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Abstract

Objective

Harvesting of the right internal thoracic artery (RITA) under direct vision, through a left minithoracotomy, without robotic or thoracoscopic assistance has never been done or described before. Bilateral internal thoracic arteries (BITAs) in coronary artery bypass grafting (CABG) have shown greater survival and freedom from reintervention. The aim was to develop a multivessel minimally invasive CABG technique in which the BITAs are harvested under direct vision and complete revascularization of the myocardium is done by the off-pump method, using only BITAs (left internal thoracic artery [LITA]–RITA Y) through a 2-in left minithoracotomy, without robotic/thoracoscopic assistance—the “Nambiar Technique.”

Methods

From August 2011 to December 2012, a total of 150 patients underwent off-pump minimally invasive multivessel CABG using BITAs, through a 2-in left minithoracotomy incision. Both internal thoracic arteries were harvested directly under vision, and complete revascularization of the myocardium was done using the LITA-RITA Y composite conduit, followed by flow study of the grafts. Coronary artery stabilization for anastomoses was done by using epicardial stabilizers introduced through the minithoracotomy.

Results

One hundred fifty patients had minimally invasive total arterial myocardial revascularization using BITAs (LITA-RITA Y composite conduit) via a left minithoracotomy. The mean number of grafts was 2.8. A total of 81.6% of the patients had three grafts. Ejection fraction was 34.5 ± 5.2. There was one mortality but no major morbidity. The RITA and LITA harvest times were 39.5 ± 11.2 and 35.2 ± 8.6 minutes, respectively. The total time in the operating room (including extubation) was 331.5 ± 42.5 minutes, and operating time was 240.8 ± 24.6 minutes. One hundred twenty-six patients (87.7%) were extubated on the table. The mean hospital stay was 3.1 days. One patient (0.6%) had an elective conversion to sternotomy because the flow in the LITA-RITA Y composite conduit was inadequate and had saphenous vein grafts. Coronary angiograms were done in 37 patients (25%); and computed tomographic angiograms, in 33 patients (22%), and the grafts were patent. Stress test was done in 80 patients (53%), which had normal findings.

Conclusions

The Nambiar Technique encompassed using a 2-in left minithoracotomy incision through which the BITAs were conveniently harvested in a skeletonized manner under direct vision without robotic or thoracoscopic assistance. Multivessel total arterial revascularization was then done using the LITA-RITA Y composite conduit by the off-pump methodology. The early outcomes have been excellent, and coronary angiograms showed widely patent grafts. This technique is reproducible and can be done on an empty beating heart to aid in training.

Harvesting of the right internal thoracic artery (RITA) under direct vision through a left minithoracotomy, without robotic or thoracoscopic assistance, has never been done or described before. The “Nambiar Technique” encompassed harvesting of bilateral internal thoracic arteries (BITAs) under direct vision through a 2-in left minithoracotomy without robotic or thoracoscopic assistance and using the harvested BITAs, as a left internal thoracic artery (LITA)–RITA Y composite conduit, for total arterial revascularization of the myocardium by the off-pump methodology. The aim of this study was to bring together and also show feasibility of harvesting BITAs under direct vision, total arterial grafting (BITAs), minimally invasive coronary surgery (MICS), avoidance of sternotomy, reproducibility, and excellent outcomes.

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METHODS

From August 2011 to December 2012, a total of 150 patients underwent minimally invasive total arterial coronary artery bypass grafting (CABG) through a 2-in left minithoracotomy incision with the BITAs harvested under direct vision. Total arterial revascularization of the myocardium was done using the LITA-RITA Y composite conduit. Exclusion criteria were emergency surgery, pectus excavatum, severe chronic obstructive pulmonary disease, and redo surgery. The intention to treat was complete myocardial revascularization using the LITA-RITA Y composite conduit by the MICS–off-pump CABG technique through a 2-in left minithoracotomy. All patients had both mammary arteries studied during coronary angiogram preoperatively. Informed consent and institutional review board approval were taken for this study. Preoperative characteristics are detailed in Table 1.

TABLE 1
TABLE 1
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Surgical Technique and Postoperative Management (Video Attached)

The patients were placed in a supine position, with slight elevation of the left side of the chest to approximately 30 degrees. The nondominant arm with normal modified Allen test was abducted to 90 degrees and placed on an arm support (in case the radial artery was required). A video of the Nambiar Technique, supplemental digital content 1, is available online at http://links.lww.com/INNOV/A33, and additional figures of the technique, supplemental digital content 2, are available online at http://links.lww.com/INNOV/A34.

  • The patients were intubated with a double-lumen endotracheal tube for single-lung ventilation, and standard invasive monitoring with arterial line, pulmonary artery catheter, and transesophageal echocardiography was done.
  • Surface marking of the RITA and the LITA were done using a vascular Doppler and skin-marking pencil.
  • A 2-in left inframammary incision was made two fingerbreadths lateral to the LITA surface marking, and the thoracic cavity was entered through the fifth intercostal space. Using a minimal access intercostal retractor (Fehling Inc) in the fifth intercostal space, the ribs were gently spread. The pericardium was then opened in an inverted T fashion, and the coronary arteries were inspected, after which the pericardiotomy was closed with interrupted 2-0 silk sutures (Fig. 1).
  • A Thorac-Pro internal thoracic artery (ITA) (Fehling Surgical Instruments Inc, Karlstein, Germany) retractor was then used in tandem with the minimal access intercostal retractor, and the chest was elevated (Figs.2, 3). The left hemithorax was thoroughly inspected, and flow in the LITA was studied with a vascular Doppler. The fatty attachments between the pericardium and the sternum were completely divided, and on dissecting the pleural from the endothoracic fascia of the right chest wall, the RITA was well visualized (Fig. 4).
  • For enhanced visualization of the lower thirds of and beyond the bifurcation, a 0.5-in subxiphoid incision was made, and a langenbeck retractor insinuated on the undersurface of the sternum. Traction was then given via a Rultract ITA retractor, thereby elevating the lower third of the sternum, which greatly enhanced visualization of the distal end of the RITA. This incision was later used to insert a pleural drain (Fig. 2).
  • The right pleura was widely opened because this helped in positioning the circumflex vessels for grafting without any hemodynamic compromise. Using a bovie at a very low setting, the RITA was harvested in a skeletonized fashion from the subclavian vein proximally to the bifurcation distally. The RITA length was more than adequate to reach the right coronary artery and the right coronary-posterior descending artery. The LITA was then harvested in a standard fashion.
  • After heparinization, a LITA-RITA Y composite conduit was constructed, and this was used for complete myocardial revascularization by the off-pump CABG technique using only the Guidant Acrobat coronary artery stabilizer (Fig. 5). The pericardial fat was removed thoroughly to facilitate exposure. An incision was made on the anterior surface of the pericardium, and the left anterior descending artery was exposed. For the lateral and inferior wall vessels, the pericardial incision was extended to the diaphragm and to the phrenic nerve on the left side and as far as possible to the right.
  • Positioning of the heart was further aided by traction sutures on the pericardial edges and by rotation of the operating table. The LITA was anastomosed to the LAD, and the RITA Y was used for sequential grafting of the circumflex and inferior wall vessels (Figs. 6, 7).
  • Most of the patients were extubated on the table and were mobilized within an hour of return from the operating room (OR). Analgesia was optimized using the continuous paravertebral block technique with an infusion of 0.25% sensoricaine. All monitoring lines and chest drains were removed on the first postoperative morning. Most of the patients were discharged on the second or the third postoperative day.
Figure 1
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Figure 2
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Figure 5
Figure 5
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Figure 6
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Figure 7
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RESULTS

Of the 150 patients who had minimally invasive total arterial CABG, the operation was completed without conversion in 149 patients (99.3%). The mean number of grafts was 2.8. Distribution of the conduits and the target vessels is detailed in Table 2. A total of 126 patients (87.7%) were extubated in the OR. The mean duration of stay was 3.1 days. There was one mortality but no major morbidity. Mortality was due to sepsis and multiorgan failure.

TABLE 2
TABLE 2
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There were minimal postoperative atrial fibrillation and pleural effusion. The strategy for prevention of postoperative atrial fibrillation was as follows: intravenous (IV) bolus of 150 mg of amiodarone was given before the initial anastomosis, then another IV bolus of 150 mg was given after completion of revascularization. This was then followed by infusion of 900 mg of amiodarone for 24 hours. Two grams of IV magnesium sulphate was also given intraoperatively. Two hundred milligrams of oral amiodarone twice a day was continued for a week. The QT intervals were monitored daily.

Follow-up was complete in 138 patients (92%). The mean duration of follow-up was 9.5 months (range, 3–17 months). Imaging studies were done at 3 months, the rationale being to check for early graft patency. The patients had only one study methodology. Because all the patients who underwent surgery were feeling very well and had no complaints, only 37 (25%) consented for an angiogram. Thirty-three patients (22%) opted for a computed tomographic angiogram, and the rest, 80 patients (53%), consented for a stress test. All grafts studied by coronary and computed tomographic angiogram were patent, and the stress tests done showed normal results.

There was no late mortality or recurrence of angina on follow-up. None of the patients had any reintervention. Distribution of conduits and target vessels is shown in Table 2, and operative characteristics and results are shown in Tables 3 and 4.

TABLE 3
TABLE 3
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TABLE 4
TABLE 4
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Comments

Use of BITAs in CABG has shown improved survival and increased freedom from reintervention.1 Total arterial revascularization with composite arterial grafts has clearly improved the midterm and long-term outcomes.2 However, the use of BITAs has not been optimal in CABG because of increased incidence of sternal complications especially in patients with diabetes.

The approach for minimal access coronary bypass surgery has been an anterior approach for grafting of the left anterior descending artery with a pedicled ITA conduit.3 Calafiore and colleagues4 popularized minimally invasive CABG through a small left anterior thoracotomy and reported the largest series, extending the indication to patients with multivessel coronary disease. McGinn et al5 have shown that in MICS CABG, applicability, revascularization completeness, morbidity profile, and safety were excellent and were maintained despite rapid procedural adoption. However, there was no use of BITAs harvested under direct vision via a left minthoracotomy.

Harvesting of ITAs with conventional thoracoscopic instruments with video assist has been limited because of lack of precision, instrument factors, and limitations.3 The introduction of robots has added to the total endoscopic harvest of the ITAs; however, the limitations have been the cost factor, availability, and steep learning curve.6

Subramanian and colleagues3 reported BITA harvesting with robotic assistance and minimal access multivessel coronary artery bypass. Robotic assistance greatly enhances visualization and thereby results in harvesting longer lengths of conduits, which is essential for multivessel grafting.7,8 In our study, for enhanced visualization of the lower thirds of the RITA and the LITA and also in increasing the space required for manipulation of the heart, a 0.5-in subxiphoid incision was made through which a langenbeck retractor was insinuated on the undersurface of the sternum and traction was given using a Rultract ITA retractor. This elevated the undersurface of the sternum and enabled us not only to manipulate with ease the minimal access instruments within the thorax but also to visualize the distal ends of both the RITA and the LITA. This resulted in our ability to harvest conduits of more than adequate length for complete arterial revascularization. This incision was later used to insert a pleural drain. Further, avoiding a median sternotomy, BITAs were used without increasing the risk for wound dehiscence, noting particularly the large number of patients with diabetes in our study group.

Multivessel coronary artery bypass through minimal access has been performed using peripheral arterial cannulation and cardioplegic arrest.9,10 Our technique encompassed a method in which through a 2-in left minithoracotomy, BITAs of adequate length were conveniently harvested in a skeletonized manner under direct vision. Total arterial off-pump complete myocardial revascularization was then done using the LITA-RITA Y composite conduit. This grossly reduced the invasiveness when compared with CABG through a sternotomy.

Vassiliades11 has described port-access stabilization in endoscopic coronary artery bypass for LITA to left anterior descending artery anastomoses. In our study, we have used the Acrobat Suv coronary artery stabilizer for positioning and stabilization of all coronary targets. The use of intraoperative transesophageal echocardiography while positioning for the various grafts preempted any hemodynamic instability.

The postoperative recovery was good, with most of the patients being extubated on the OR table. Operating times were comparable with standard CABG, and postoperative pain was well controlled with paravertebral block using continuous sensoricaine infusion for 24 hours. The hospital stay was minimal, with the mean hospital stay being 3.1 days. This compares favorably with other studies.3 Financial benefits for both the patient and the hospital were also observed. The early outcomes have been good, and coronary angiograms carried out showed widely patent grafts. A limitation of this study has been the absence of postoperative coronary angiograms at 12 months and late graft patency data. However, we have used markers such as stress test, freedom from death, cardiac-related events, and reintervention for graft patency. None of the patients have had any reintervention.

Diegeler et al12 have shown minimally invasive direct coronary artery bypass grafting to be a safe procedure and have also shown this in patients with multiple-vessel coronary artery disease and for patients with severely reduced left ventricular (LV) function. In our study, we have shown the safety of the technique as demonstrated by the low incidence of perioperative and postoperative complications including morbidity. Potential contraindications to this technique are severe chronic obstructive pulmonary disease, Po2 of less than 60 on room air arterial blood gas moderate to severe renal dysfunction, recent myocardial infarction or cerebrovascular accident, and multivessel CABG in hearts with poor ejection fraction (<25%).

We carried out the first 40 cases on the patients with good LV function. As our experience with this technique increased, we started carrying out coronary artery bypass on the patients with lower ejection fractions and finally on the patients with very poor LV function (<20%) having multivessel disease without other targets to bypass than the left anterior descending artery. This technique, we feel, is reproducible; requires the same infrastructure for formal coronary bypass surgery, with the exception being the acquisition of minimally invasive cardiac surgical instrumentation; and can be done on an empty beating heart to aid in training.

In conclusion, we feel that this novel technique will help optimize MICS and the use of BITAs with its associated benefits, without the invasiveness and related complications of a median sternotomy, especially in patients with diabetes. Further, this may allay patient fears of heart surgery and also has the potential for decreased patient morbidity, shorter hospital stay, early return to active life, financial benefits, and good cosmesis (Fig. 8).

FIGURE 8
FIGURE 8
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REFERENCES

1. Lytle BW, Blackstone EH, Loop FD . Two internal thoracic artery grafts are better than one. J Thorac Cardiovasc Surg. 1999; 117: 855–872.

2. Muneretto C, Negri A, Manfredi J . Safety and usefulness of composite grafts for total arterial myocardial revascularization: a prospective randomized evaluation. J Thorac Cardiovasc Surg. 2003; 125: 826–835.

3. Subramanian VA, Patel NU, Patel NC, Loulmet DF . Robotic assisted multivessel minimally invasive direct coronary artery bypass with port-access stabilization and cardiac positioning: paving the way for outpatient coronary surgery? Ann Thorac Surg. 2005; 79: 1590–1596.

4. Calafiore AM, Di Giammarco G, Teodori G, et al. Left anterior descending coronary artery grafting via left anterior small thoracotomy without cardiopulmonary bypass. Ann Thorac Surg. 1996; 61: 1658–1663.

5. McGinn JT Jr, Usman S, Lapierre H, Pothula VR, Mesana TG, Ruel M . Minimally invasive coronary artery bypass grafting: dual-center experience in 450 consecutive patients. Circulation. 2009; : 120:(suppl): S78–S84.

6. Jones B, Desai P, Poston R . Establishing the case for minimally invasive, robotic-assisted CABG in the treatment of multivessel coronary artery disease. Heart Surg Forum. 2009; 12: E147–E149.

7. Cichon R, Kappert U, Schneider J, et al. Robotic-enhanced arterial revascularization for multivessel coronary artery disease. Ann Thorac Surg. 2000; 70: 1060–1062.

8. Dogan S, Aybek T, Andressen E, et al. Totally endoscopic coronary artery bypass grafting on cardiopulmonary bypass with robotically enhanced telemanipulation: report of forty-five cases. J Thorac Cardiovascular Surg. 2002; 123: 1125–1131.

9. Gulielmos V, Knaut M, Cichon R, et al. Minimally invasive surgical treatment of coronary artery multivessel disease. Ann Thorac Surg. 1998; 66: 1018–1021.

10. Gulielmos V, Brandt M, Knaut M, et al. The Dresden approach for complete multivessel revascularization. Ann Thorac Surg. 1999; 68: 1502–1505.

11. Vassiliades TA Jr . Endoscopic-assisted atraumatic coronary artery bypass. Asian Cardiovasc Thorac Ann. 2003; : 11: 359–361.

12. Diegeler A, Matin M, Falk V, et al. Quality assessment in minimally invasive coronary artery bypass grafting. Eur J Cardiothorac Surg. 1999; 16:(suppl 2): S67–S72.

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CLINICAL PERSPECTIVE

This case series of 150 patients describes a technique to perform off-pump minimally invasive multi-vessel coronary artery bypass grafting using bilateral internal mammary arteries through a small left mini-thoracotomy incision. The mammary arteries were harvested under direct vision without robotic or thoracoscopic assistance. There was one mortality and the average hospital stay was just over three days. There was only one elective conversion to sternotomy. Coronary angiography was done in 37 patients and there were no graft occlusions.

This is an interesting approach which can be done with conventional instrumentation. Early outcomes were very good. The weakness of the study was the absence of graft assessment in the majority of patients. There also was no intraoperative assessment with flow probes. Finally, this represents a single-surgeon experience and it is unclear whether this technique is either widely applicable or reproducible. Future confirmatory studies from other groups will be needed to judge the clinical utility of this technique.

Keywords:

Minimally invasive; Coronary bypass; Bilateral internal thoracic arteries; Left minithoracotomy

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