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Muhivessel Coronary Artery Bypass Grafting Without Cardiopuhnonary. Bypass Mark W. Connolly, Valavanur A. Subramanian, and Nilesh U. Patel -~]]['ultivessel coronary artery bypass grafting (CABG) •165 thout cardiopulmonary bypass, commonly known as off-pinup CABG (OPCAB), has been gaining acceptance as a surgical procedure for complete surgi- cal coronary revascularization. The successful reports of "beating heart" CABG using full sternotomy by Bennetti, 1 Buffolo, 2 and Pfister, 3 and using minimal access approaches by Subramanian 4 and Calafriore, 5 has led to the development of stabilizer retractor platforms that enable successfnl coronary-artery con- duit anastomoses. The primary goal of surgical coro- nary artery revascularization, regardless or whether or not cardiopulmonary bypass is used, is successful complete CABG with low hospital morbidity and mortal- ity, and long-term pateney of grafts to ensure long-term, coronary event-free and quality patient survival. Achieving this goal without the potential complications of cardiopuhnonary bypass is under investigation in many centers. In March 1999, we embarked on a committed OPCAB program, and currently we perform more than 97% of our CABG procedures without cardiopulmonary bypass. Patient Selection All CABG patients are potential candidates for OPCAB muhivessel surgery with the absolute exception of two patient subsets. Patients with a deep intramyocardial left anterior descending (LAD) artery traversing on the right ventricular cndocardium or with a coronary artery that requires an extensive long endarterectomy will usually require cardiopulmonary bypass for success- ful grafting. Candidates for OPCAB surgery may include patients needing muhiple grafts, including sequential coronary anastomoses; those with poor left ventricular; those with large cardiomegalie hearts; those with low ejection fraction (<30%); those with acute myocardial isehemia and/or recent myocardial infarction; those with poor diabetic distal vessels; and those requiring short cndar- terectomies (<3 cm), atrioventrieular (AV) groove anas- tomoses, and muhiple arterial grafts. As one begins an OPCAB program, selecting patients with normal-sized hearts, good left ventricular ftmc- tion, good distal targets, and requiring only grafting of anterior (LAD and diagonals) and posterior (right cordnary artery [RCA], posterior descending artery 166 Operative Techniques in Thoracic and [PDA], posterior lateral ascending artery [PLA]) ves- sels is advised. As comfort with the teclmique increases, the surgeon can expand patient selection to include those with good ventricular function requiring circum- flex artery revascularization. Eventually, the surgeon can select patients with more difficult anatomy and pathology, such as those patient subsets mentioned earlier. Anesthesia and Intraoperative Molritoring To perform successful OPCAB surgery, the surgeon and cardiac anesthesiologist must work closely as a team tlwoughout the entire procedure. Standard cardiac anesthetic techniques for induction and maintenance of anesthesia are used. Because many 0PCAB patients are extubated oll the operating room (OR) table or less than 4 hours postoperatively in the intensive care unit (ICU), 0PCAB patients usually receive a lower narcotic dosage titan cardiopuhnonary bypass patients. Hemodynamic monitoring with a radial arterial line, oxymetric Swan- Ganz catheter, electrocardiography (ECG), indwelling urinary catheter, and transesophageal echocardiogra- phy (TEE) are standard on every OPCAB case. Oxymet- tic Swan-Ganz monitoring of potential deteriorating mixed venous saturations may be the earliest indicator of hemodynamic deterioration. Pulmonary pressure and thermodilution cardiac output are not always indicative of bemodynamic compromise when the heart is meclmnically dislocated. TEE is used for evaluation of left ventricular function, regional wall motion, and valvular abnormalities. Assessment of the degree of aortic valve and/or mitral valve regurgitation, which may worsen with manipulation of the heart, is critical information. For instance, in a patient with an ejection fraction of 30%, 1 to 2+ mitral regurgitation and moderately elevated pulmonary pressures, the anesthe- siologist may .choose an intraoperative phosphodiester- ase inhibitor to improve left ventricular function and decrease mitral regurgitation and puhnonary pressures before manipulation of the heart--possibly preventing conversion to cardiopulmonary bypass. The etiolog T of llemodynamic deterioration is myocar- dial ischemia during coronary artery occlusion and/or excessive displacement and compression of the heart. Brief "trial" I)eriods of 2 to 3 minutes of coronary occlusion while the anestbesiolo~st monitors the pa- Cardiovascular Surgery, Vol 5, No 3 (Au~tst), 2000: pp 166-175

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Page 1: Muhivessel Coronary Artery Bypass Grafting Without ... · Muhivessel Coronary Artery Bypass Grafting Without Cardiopuhnonary. Bypass Mark W. Connolly, Valavanur A. Subramanian, and

Muhivessel Coronary Artery Bypass Grafting Without Cardiopuhnonary. Bypass

Mark W. Connolly, Valavanur A. Subramanian, and Nilesh U. Patel

-~]]['ultivessel coronary artery bypass grafting (CABG) •165 thout card iopulmonary bypass, commonly known as off-pinup CABG (OPCAB), has been gaining acceptance as a surgical procedure for complete surgi- cal coronary revascularization. The successful reports of "beating hear t " CABG using full sternotomy by Bennetti, 1 Buffolo, 2 and Pfister, 3 and using minimal access approaches by Subramanian 4 and Calafriore, 5 has led to the development of stabilizer retractor platforms that enable successfnl coronary-artery con- duit anastomoses. The primary goal of surgical coro- nary artery revascularization, regardless or whether or not cardiopulmonary bypass is used, is successful complete CABG with low hospital morbidity and mortal- ity, and long-term pateney of grafts to ensure long-term, coronary event-free and quality patient survival. Achieving this goal without the potential complications of cardiopuhnonary bypass is under investigation in many centers. In March 1999, we embarked on a committed OPCAB program, and currently we perform more than 97% of our CABG procedures without cardiopulmonary bypass.

P a t i e n t Se l ec t i on

All CABG patients are potential candidates for OPCAB muhivessel surgery with the absolute exception of two patient subsets. Patients with a deep intramyocardial left anterior descending (LAD) artery traversing on the right ventricular cndocardium or with a coronary artery that requires an extensive long endarterectomy will usually require cardiopulmonary bypass for success- ful grafting.

Candidates for OPCAB surgery may include patients needing muhiple grafts, including sequential coronary anastomoses; those with poor left ventricular; those with large cardiomegalie hearts; those with low ejection fraction (<30%); those with acute myocardial isehemia and/or recent myocardial infarction; those with poor diabetic distal vessels; and those requiring short cndar- terectomies (<3 cm), atrioventrieular (AV) groove anas- tomoses, and muhiple arterial grafts.

As one begins an OPCAB program, selecting patients with normal-sized hearts, good left ventricular ftmc- tion, good distal targets, and requiring only grafting of anterior (LAD and diagonals) and posterior (right cordnary artery [RCA], posterior descending artery

1 6 6 Operative Techniques in Thoracic and

[PDA], posterior lateral ascending artery [PLA]) ves- sels is advised. As comfort with the teclmique increases, the surgeon can expand patient selection to include those with good ventricular function requiring circum- flex artery revascularization. Eventually, the surgeon can select patients with more difficult anatomy and pathology, such as those patient subsets mentioned earlier.

Anes thes ia and I n t r a o p e r a t i v e Molr i tor ing

To perform successful OPCAB surgery, the surgeon and cardiac anesthesiologist must work closely as a team tlwoughout the entire procedure. Standard cardiac anesthetic techniques for induction and maintenance of anesthesia are used. Because many 0PCAB patients are extubated oll the operating room (OR) table or less than 4 hours postoperatively in the intensive care unit (ICU), 0PCAB patients usually receive a lower narcotic dosage titan cardiopuhnonary bypass patients. Hemodynamic monitoring with a radial arterial line, oxymetric Swan- Ganz catheter, electrocardiography (ECG), indwelling urinary catheter, and transesophageal echocardiogra- phy (TEE) are standard on every OPCAB case. Oxymet- tic Swan-Ganz monitoring of potential deteriorating mixed venous saturations may be the earliest indicator of hemodynamic deterioration. Pulmonary pressure and thermodilution cardiac output are not always indicative of bemodynamic compromise when the heart is meclmnically dislocated. TEE is used for evaluation of left ventricular function, regional wall motion, and valvular abnormalities. Assessment of the degree of aortic valve and/or mitral valve regurgitation, which may worsen with manipulation of the heart , is critical information. For instance, in a patient with an ejection fraction of 30%, 1 to 2+ mitral regurgitation and moderately elevated pulmonary pressures, the anesthe- siologist may .choose an intraoperative phosphodiester- ase inhibitor to improve left ventricular function and decrease mitral regurgitation and puhnonary pressures before manipulation of the heart--possibly preventing conversion to cardiopulmonary bypass.

The etiolog T of llemodynamic deterioration is myocar- dial ischemia during coronary artery occlusion and/or excessive displacement and compression of the heart. Brief " t r i a l " I)eriods of 2 to 3 minutes of coronary occlusion while the anestbesiolo~st monitors the pa-

Cardiovascular Surgery, Vol 5, No 3 (Au~tst), 2000: pp 166-175

Page 2: Muhivessel Coronary Artery Bypass Grafting Without ... · Muhivessel Coronary Artery Bypass Grafting Without Cardiopuhnonary. Bypass Mark W. Connolly, Valavanur A. Subramanian, and

OfF-rUMP CABC 1 6 7

tient's hemodynamic parameters is usually all that is necessary to determine whether a particular heart position will be tolerated while a coronary anastomosis is completed. Pbarmacolo~c agents such as neosyneph- rine to increase arterial perfusion pressure, nitroglycer- ine to reduce volume in a full heart and improve coronary flow, phosphodiesterase inhibitors to improve contractility and decrease pulmonary hypertension, and beta-blocking agents to lower the heart rate are used as needed. Crystalloid fhfid volume replacement is given judiciously to prevent hemodilution. An autolo- gous cell saver is used routinely for muhivessel OPCAB, as 300 to 1000 cc of blood can be salvaged secondary to hemorrhage from sternal marrow, coronary arterioto- mies, and surgical sites. Tile patient's body temperature is maintained by increasing temperature and providing intravenous fluid warmers, warmed-lmmidified ventila- tion, a heated bed blanket, and warm irrigation in tile surgical fiehl. Maintaining close to normothermic body temperature is crucial if tile patient is to be extubated in the OR after the procedure. Local anesthesia (e.g., Marcaine) is injected into the sternal wound to decrease early postoperative pain.

Surg ica l A p p r o a c h

Because the OPCAB teclmique produces periods of myocardial ischemia from coronary artery occlusion during anastomotic grafting, the order of grafting is important and must be carefully planned based on the patient's preoperative coronary an~ogram. Before each anastomosis, the surgeon needs to evaluate whether enough myocardium is at ischemic risk during coronary artery occlusion to pose a risk for hemodynamic deterio- ration. We have developed some guidelines:

1. Perform the LAD or diagonal-LAD graft- ing first to revascularizethe septum anti

anterior wall, except in moderate (<80% stcnosis) LAD disease with a total RCA occlusion, graft the RCA or tile PDMPLA first to reperfuse the inferior wall collater- alized from the LAD.

2. In large, dominant RCA vessels that are not totally occluded, use an intracoronary shunt or distal perfusion to prevent heart block.

3. Slmnt large, moderately stenosed (<80%) intermediate ramus arteries, because the combination of anteriolateral ischemia and medial displacement of the heart with right ventricular outflow tract compres- sion can lead to rapid hemodynamic dete- rioration.

4. In patients with acute myocardial isch- emia, critical (>90%) left main disease with or without total RCA occlusion, or a large heart with low ejection fraction, graft tile LAD first with nfinimal manipu- lation of the heart. Excessive manipula- tion can quickly lead to global ischenda and the need for conversion to cardiopul- monary bypass. Deep pericardial sutures can be placed after LAD grafting.

Intracoronary shunts are used in 10% to 15% of cases. Proximal anastomosis can be performed before distal anastomosis or after grafting of critical distal coronary arteries to perfuse the myocardimn and prevent ischemic complications. With proper planning and use of fllese methods, distal perfusion techniques sholfld not be needed. If tile inte~'ity of the coronary anastomosis is in cptestion, an intraoperative coronary flowmeter (CTS Coro- nary Flowmeter System, CTS-Glfidant, Cupertino, CA) can be used to assess graft patency and flow.

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] 6 8 CONNOLIA, SUBRAMANIAN, AND I~,TEL

SURGICAL TECilNIQUE

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1 A full midline sternotomy incision is made extending inferior to tile xiphoid, to enable wide lateral retraction of the sternunl. As tile retractor is opened, tile right sternum is pulled anteriorly while tile left stermnn is imslled posteriorly. This allows for possible displacement of the apex of tile heart under the right sternum during circumflex vessel grafting. The incision is extended inferiorly another 4 cm if right gastroepiploic artery harvesting is needed. The pericardium is opened widely along the diaphra~n and extended down to the inferior vena eava to increase the laxity of the right pericardiunl. This decreases right heart compression when the Ileart is displaced to the right. The entire right pleural space may be opened to disldace the heart into the right pleural space when grafting circumflex arteries or large hearts. No right-sided pericardial sutures are placed; these sutures would increase right pericardial tension and potential meclmnieal compres- sion of the rigllt heart, leading to hemodynamic deterioration.

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OFF-PUMP CABG 1 6 9

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2 Left superficial pericardial sutures are placed to pull the pericardium up to the left sternum. Tile apex of the heart is gently i)ulled right lateral and anterior to expose the left posterior pericardium. Deep pericardial sutures are placed in three positions: just medial to tlle inferior vena cava (IVC) in the diaphra~natic pericardimn, between the IVC and tile left inferior puhnonary vein under the posterior left atrium, and just anterior to the left inferior puhuonary vein below the left phrenic nerve. The heart is gently retracted and placed back into the pericardial well with each stiture placed to prevent prolonged hemodynamic compromise. Ilaving the ancsthesiolo~st briefly hold mechanical ventilation will increase exposure for this step. These deep pericardial sutures are then pulled to varying degrees of tension, displacing the heart for exposure of the desired coronary artery. The surgeon nmst avoid taking deep bites through the pericardium xdth these sutures, as puncture of the left hmg and hilar structures can occur. The sutures should remain below tile left phrenic nerve to prevent injury.

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170 CONNOLIX, SUBR~L'tL%NIAN, AND PATEL

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3 LAD and diagonal anastomosis. Tile deep pericardial sutures are gently pulled to bring the LAD midline and up into tile surgical field. Tile coronary artery is llalpated and the anastomosis site inspected. Silastic tapes are placed proximal and distal to tile anastomosis site. Tile retractor (CTS Access Ultima System; Guidant-CTS, Cupertino, CA) is slid into position to stabilize the coronary artery. Gentle compression around the I~kD on tile left ventricle can achieve stabilization without compromising hemodynamies.

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4 Coronary anastomosis. The proximal Silastic tapes are gently crossed, and tile distal tapes are gently pulled inferiorly (not crossed) to decrease coronary blood flow. Excessive crossing of distal tapes may injure tile coronary artery. Tile epicardium over tile vessel is dissected with a scalpel or scissors. The arteriotomy is performed ~i th an iris blade. After tile arteriotomy is extended with coronary scissors; lateral 6-0 silk retraction sutures may be used to open tile arteriotomy and increase stabilization if necessary. Tile in-situ left internal mammary ar tery is auastomosed to the LAD or sequentially to the diagonal-LAD in the s tandard fashion. A CO, mist blower is used to briefly blow away coronary blood and improve visibility during suture placement. An intraeoronary shunt may be nsed to perfnsc tile distal ar tery during the procedure to prevent myocardial ischemia. In t racoronary shunts can also be used to improve visibility if excessive blood flow from collaterals or septal perforators occurs.

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172 CONNOLL~. SUBILL~L%NIAN, AND PATEL

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5 Ciremnflex anastomoses. The deep pericardial sutures are pulled to fur ther displace tile heart to the right. The apex of the heart may be placed into tile right pleural space to improve exposure of the lateral wall. The site for anastomosis of the intermediate ramus or obtuse marginal vessel(s) is determined, Silastic tapes are placed, and tile stabilizing arm is positioned. TILe arm is usually positioned as parallel to the vessel as possible, to minimize its movement. This is important with hypertrophied, hyperdynamic ventricles that exert ontward force against the retractor. The anastomosis is completed as shown in 3. After sequential radial ar tery anastomoses are performed, the stabilizer is carefnlly hacked out from tile sequential segment, to prevent disruption and pulling on the anastomoses.

Page 8: Muhivessel Coronary Artery Bypass Grafting Without ... · Muhivessel Coronary Artery Bypass Grafting Without Cardiopuhnonary. Bypass Mark W. Connolly, Valavanur A. Subramanian, and

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6 PDA and PLA anastomosis. The IVC deep pericardial suture is pulled inferiorly, and the patient is placed in Trendelenburg position to displace the apex of the heart toward the ceiling. Silastic tapes are placed, and the stabilizing arm is positioned around the desired posterior vessel, taking care to avoid excessive stabilizer compression that displaces the apex of the heart superiorly, which can cause hemodynamic compromise. This position is usually well tolerated even in patients with low ejection fraction. Sequential grafting to the PDA and PLA is commonly performed. The right gastroepiploic artery can also be brought through a diaphra~natic slit to access the PDA.

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174 CONNOLLI; SUBRAMANIAN, AND ]'ATEL

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7 RCA anastomosis. The left deep pericardial sutures are loosened to position the heart in its normal anatomical position. Deep right inferior pcricardial sutures are placed to pull up the right heart anteriorly. Silastic tapes are placed proximally and distally around tile distal RCA. The proximal tape is pulled toward the surgeon, to bring tile RCA upward. Tile distal tape is pulled (not crossed) inferiorly to flatten tile RCA horizontally. Tile stabilizing arm is then placed around tile RCA. The acute margin of the right ventricle may need to be retracted to the left ~ith a pledgeted suture to increase exposure. In situ right internal mammary or vein grafting is then done in standard fashion. Proximal anastomoses are done in standard fashion with a partial occlusion clamp. Deairing of the aorta is performed after all proximal grafts are completed with retrograde radial artery flow before the partial occlusion clamp is released.

Page 10: Muhivessel Coronary Artery Bypass Grafting Without ... · Muhivessel Coronary Artery Bypass Grafting Without Cardiopuhnonary. Bypass Mark W. Connolly, Valavanur A. Subramanian, and

OFF-PUMP CABG 1 7 5

Pos tope ra t i ve Care

Standard postoperative institutional cardiac surgery fast-track protocols are implemented. Compared to postcardiopulmouary bypass patients, OPCAB patients are extubated earlier, require less inotropic support, have lower volume replacement requirements without postpump diuresis, antl maintain higher postoperative hemoglobin levels. In our series, the need for blood product transfusions is 65% lower than for on-pump CABG cases.

Postoperative pain is controlled with intraoperative local anestheticinjection of the sternal incision, intrave- nous nonsteroidal anti-inflammatory agents such as Ketarolac, and judicious use of intravenous narcotics to avoid respiratory depression. Most patients are extu- bated in the OR or within 4 hours of surgery. Most patients are ambulating witlfin 24 hours.

The length of hospital stay is usually 3 to 4 days, with social issues and postoperative atrial fibrillation (still occurring in 25% of OPCAB patients) the primary factors delaying discharge.

Conc lus ion

The OPCAB technique has become the standard method of surgical revascularization for nmhiple grafting at our institution, performed in more than 97% of our CABG procedures. The operative mortality in more than 800 OPCAB procedures performed since the start of our OPCAB program is 1.4%.

Reports from other centers 6-9 demonstrate compa- rable mortality rates, decreased postoperative bleed- ing, and lower costs in OPCAB patients compared to

conventional cardiopulmonary bypass CABG patients. Larger retrospective series and randomized trials are presently underway to evaluate hospital and long-term resuhs, with particular emphasis on graft patency anti neurolo~c complications.

R E F E R E N C E S

1. BenettiFJ, NaselliG, WoodM, et al: Direct myocardial revascularization ~dthout extracorporeal circulation. Chest 100:312-316, 1991

2. Buffolo E, de Amdrade JCS, Braueo JNR, et al: Coronary artery bypass grafting xdthout cardiopulmonary bypass. Ann Thorae Surg 61:63-66, 1996

3. Pfister AJ, Zaki MS, Garcia JM, et al: Coronary artery bypass ~dthout cardiopulmonary bypass. Ann Tho rae Surg 51:108-192, 1992

4. Subramanian x,~., Sani G, Benetti FJ, et al: Minimally invasive coronary bypass surgery: A muhi-center report of preliminary clinical experience. Circulation 92(suppl):645, 1995

5. Calafiore AM, DiGiammareo G, Teodori G, et al: Left anterior desceuding coronary artery grafting via left anterior small thoraeotomy without eardiopulmonary bypass. Ann Tborac Surg 61:1658-1665, 1996

6. Boyd WD, Desai ND, Del Rizzo DF, et al: Off-pump surgery decreases postoperative complications and resource utilization in the ehlerly, Auu Thorac Surg 68:1490-1493, 1999

7. Diegler A, Matin 5I, Falk V, et al: Coronary bypass grafting without cardiopulmonary bypass--Technical considerations, clinical results, and follow-up. Thoracic Cardiovase Surg 47:14-18, 1999

8. Atom KV, Flavin TF, Emery RW, et al: Safety and efficacy of off-pump coronary bypass grafting. Ann Tborae Surg 69:704-710, 2000

From the Section of Cardiovascular and Thoracic SurgeD', Lenox ttill Itospital, New York, NY.

Address reprint requests to Mark W. Connoll). MD, Section of Thoracic and Cardiovascular SurgeD, 130 E. 77th St, New York, NY 10021.

Copyright �9 2000 by W.B. Saunders Company 1522-2942100/0503 -0003 $10.00/0 doi:10.1053/otct.2000.18228