New approaches to cardiac surgery: Anesthetic implications

1
New approaches to cardiac surgeryAnesthetic
implications

• John Butterworth, MD
• Professor Head
• Section on Cardiothoracic Anesthesia
• Wake Forest University School of Medicine
• Winston-Salem, North Carolina

http//www.wfubmc.edu/anesthesia/ 
Select Education and then click on
Brazil
2
Items for Discussion

• Newer techniques for coronary revascularization
• Off-pump coronary artery bypass (OPCAB)
• Total arterial grafting
• Minimally invasive techniques
• Transmyocardial laser revascularization
• Robotic surgery

3
History of Coronary Artery Surgery

• 1951 Vineberg and Miller implant IMA in LV
• 1958 Longmire reports coronary endarterectomy
• 1961 Senning performs patch graft of stenotic
  coronary with CPB
• 1960s Sones Shirey develop coronary
  cineangiography
• 1964 Kolesov sews IMA to LAD (USSR) off pump

Ake Senning 1915-2000

• 1967 Favaloro and Effler use reversed saphenous
  veins to bypass coronary
• 1968 IMA reintroduced
• 1971 Sequential grafting
• 1990s Rise of OPCAB

Favaloro. JACC 1999331435-41
4
History of Coronary Artery Surgery

• 1951 Vineberg and Miller implant IMA in LV
• 1958 Longmire reports coronary endarterectomy
• 1961 Senning performs patch graft of stenotic
  coronary with CPB
• 1960s Sones Shirey develop coronary
  cineangiography
• 1964 Kolesov sews IMA to LAD (USSR) off pump

Frank Sones

• 1967 Favaloro and Effler use reversed saphenous
  veins to bypass coronary
• 1968 IMA reintroduced
• 1971 Sequential grafting
• 1990s Rise of OPCAB

Favaloro. JACC 1999331435-41
5
History of Coronary Artery Surgery

• 1951 Vineberg and Miller implant IMA in LV
• 1958 Longmire reports coronary endarterectomy
• 1961 Senning performs patch graft of stenotic
  coronary with CPB
• 1960s Sones Shirey develop coronary
  cineangiography
• 1964 Kolesov sews IMA to LAD (USSR) off pump

René Favaloro

• 1967 Favaloro and Effler use reversed saphenous
  veins to bypass coronary
• 1968 IMA reintroduced
• 1971 Sequential grafting
• 1990s Rise of OPCAB

Favaloro. JACC 1999331435-41
6
Comparative studies of OPCAB vs. CABG CPB in
low risk patients

• Few good studies
• I RCT
• II-1 Well designed, controlled trials not random
• II-2 Cohort or case-control studies
• II-3 Multiple time series
• III Expert opinions, clinical series, clinical
  experience

Technology Report. OPCAB. UHC 2002 Omar, Taggart.
Lancet 2002360327-9
7
Greater use of blood products in CPB (n100) vs
OPCAB (n100)
Ascione. JTCVS 2001121689-96
8
Early and midterm outcome beating heart vs.
cardioplegic arrest

• 401 patients randomly assigned
• Primary outcome all cause mortality
• Reduced AF (-25), chest infection (-12),
  inotropes (-18), rbc transfusion (-31),
  prolonged hospital (-13) or ICU (-13) LOS
• Mortality 2 vs 3
• Cardiac event or death 17 vs 21

Angelini. Lancet 2002 3591194-9
9
Association between CPB and worse morbidity and
mortality

• 10,941 consecutive CABGs (7.7 OPCAB)
• Logistic regression to adjust for differences
• No sig difference in periop MI, bleeding, or
  reoperation for bleeding
• Periop CVA OR0.26 for Off CPB/On CPB

Patel. Eur J Cardio-thorac Surg 200222255-60
10
Reduced incidence of stroke with beating heart
CABG
with postoperative stroke

• 16,184 patients undergoing cardiac surgery (CBG
  55, OPCAB 11, AV 11, MV 4, 2 or 3 valve 2,
  CABG valve 15)
• Overall stroke 4.6
• Lower incidence with OPCAB

Bucerius. Ann Thorac Surg 2003 75472-8
11
Comparative studies of OPCAB vs. CABG CPB in
high risk patients

• Few good studies
• I RCT
• II-1 Well designed, controlled trials not random
• II-2 Cohort or case-control studies
• II-3 Multiple time series
• III Expert opinions, clinical series, clinical
  experience

Technology Report. OPCAB. UHC 2002
12
Improved postoperative pulmonary status of OPCAB
vs CABG CPB

• 58 patients with severe COPD in RCT of single
  vessel CAB (CPB vs MIDCAB vs OPCAB)
• Shortest extubation time with MIDCAB
• Longest ICU LOS with CPB

Time (h) LOS (d)
Güler Ann Thorac Surg 200171152-7
13
Reduced mortality and strokes in octogenerians
having OPCAB

• 125 patients age gt80 y CPB 63 OPCAB 62
• LVF similar 54.5 vs 50.9 similar distal
  anastamoses 2.9 vs 2.6
• Operative mortality and CVA occur 4.2 times more
  often with CPB

Demaria. Circulation 2002106I-5-I-10
14
OPCAB Appears Cheaper Than CABG With CPB
Gravlee. ASA Refresher 2002 Ascione. Ann Thorac
Surg 1999682237-42
15
Anesthetic implications of OPCAB

• More work than for CABG with CPB
• Hemodynamic instability common during grafting
• Surgical speed and skill define the operation
• Transesophageal echocardiography and SVO2
  monitoring often helpful
• Rapid emergence from anesthesia (cannot hide
  behind fentanyl!)
• Coagulopathy much less common

16
Anticoagulation OPCAB vs CABG
Target ACT in Seconds During OPCAB

• Most target ACT in 400-480 range during CABG
• Lesser degrees of heparinizatin sought during
  OPCAB by n304 surgeons 67 use smaller heparin
  dose
• Generally no need for antifibrinolytics

DAncona. Heart Surg Forum 20014354-8 Shore-Less
erson Gravlee CPB chapter 22
17
Total arterial grafting

• Left internal mammary (thoracic) artery
• Right internal mammary (thoracic) artery
• Gastroepiploic artery
• Left or right radial artery
• Jump grafts

18
Anesthetic implications of total arterial grafting

• Longer time delay for harvesting conduit
• Communication with surgeon re placement of
  intravenous and arterial cannulae
• Uncertain risk of acute vasospasm many drugs
  used prophylactically (nitroglycerin, diltiazem,
  etc.)
• Longer-lasting revascularization for the patient

19
Other minimally invasive techniques

• Beating heart
• MIDCAB
• Video assisted direct CAB
• Total endoscopic CAB
• Robotic surgery
• OPCAB with thoracic epidural

• Arrested heart
• Port-access CAB
• Port-access valves
• ASD closure

Ganapathy. Best Pract Res Clin Anaesth
20021663-80
20
Minimally invasive direct coronary artery bypass
(MIDCAB)

• Approach
• L or R anterior thoracotomy
• Ministernotomy
• Epigastric
• Endoscopic harvest of IMA, radial, or vein
• Video assistance
• Robotic assistance

• Anesthetic concerns
• Increased duration
• Double lumen tube
• Conversion to sternotomy and/or CPB

Ganapathy. Best Pract Res Clin Anaesth
20021663-80
21
Minimally invasive direct coronary artery bypass
(MIDCAB)

• Approach
• L or R anterior thoracotomy
• Ministernotomy
• Epigastric
• Endoscopic harvest of IMA, radial, or vein
• Video assistance
• Robotic assistance

• Anesthetic concerns
• Increased duration
• Double lumen tube
• Conversion to sternotomy and/or CPB

Ganapathy. Best Pract Res Clin Anaesth
20021663-80
22
Potential advantages of thoracic epidural
analgesia for cardiac surgery

• Reduction of neuroendocrine stress response
• Effects on hemodynamics
• Metabolism
• Immune responses/SIRS
• Adverse effects of opioids
• Cardiac sympathectomy
• Improved GI motility
• Intense postoperative analgesia

Chaney. Ch 4 in Regional Anesthesia for Cardiac
Surgery, 2002 Liu, Carpenter, Neal.
Anesthesiology 1995821474-1506
23
Potential disadvantages of thoracic epidural
analgesia for cardiac surgery

• Awake patient
• Pneumothorax
• Cardioversion or defibrillation
• Unknown risk of hematoma
• Benefit may be small (no convincing clinical
  trials yet published)
• Topic covered in another lecture

Chaney. Ch 4 in Regional Anesthesia for Cardiac
Surgery, 2002 Liu, Carpenter, Neal.
Anesthesiology 1995821474-1506
24
Other minimally invasive techniques

• Beating heart
• MIDCAB
• Video assisted direct CAB
• Total endoscopic CAB
• Robotic surgery
• OPCAB with thoracic epidural

• Arrested heart
• Port-access CAB
• Port-access valves
• ASD closure

Ganapathy. Best Pract Res Clin Anaesth
20021663-80
25
Port-access surgery on the arrested heart

• Suitable for coronary, AVR, MVR, ASD, myxoma
• R lateral thoracotomy or ministernotomy
• CPB via femoral artery and vein (suction assisted
  drainage)
• Coronary sinus (CS)
• TEE or fluoroscopy
• Endoaortic balloon (EA)

CS
EA
CS
PAC
Ganapathy. Best Pract Res Clin Anaesth
20021663-80
26
Items for Discussion

• Newer techniques for coronary revascularization
• Off-pump coronary artery bypass (OPCAB)
• Total arterial grafting
• Minimally invasive techniques
• Transmyocardial laser revascularization
• Robotic surgery

27
Rationale for transmyocardial laser
revascularization

• Increasing incidence of coronary disease
• Not always amenable to PTCI or CABG
• Laser creates new channels to bring oxygenated
  blood to myocardium
• Angiogenesis will follow?

Masson trichrome stain of laser channel after 9
months Domkowski. Circulation 2001103469-71
Saririan. JACC 200341173-83
28
Rationale for TMR

• Epicardial approach (surgery)
• Endocardial approach (percutaneous)
• Holmiumyttrium argon garnet (HoYAG) CO2
  lasers approved by US Food and Drug Admin

• HoYAG beam transmitted by optical fiber
• CO2 laser beam transmitted by mirrors and lenses
• Different lasers have not been compared in
  clinical trials

29
Technique of TMR vs PMR

• TMR
• L anterior thoracotomy or median sternotomy
• Cannulation and heparin needed ONLY if concurrent
  CABG
• 25-50 channels made with 1 cm separation in L
  ventricle

• PMR
• 3 catheter based HoYAG devices
• Lack FDA approval
• Introduced into LV via femoral artery
• Laser against endocardium
• Multiple pulses to create up to 20 channels

30
Mechanism of actionlaser revascularization

• Open channel hypothesis (similar to sinusoids in
  reptile hearts)
• Myocardial denervation
• Angiogenesis
• Does not increase blood flow acutely
• Increases blood flow after 2-6 months

Hematoxylin and eosin stain shows new blood
vessels containing erythrocytes after 9
months Domkowski. Circulation 2001103469-71
31
Mechanism of actionlaser revascularization

• Open channel hypothesis (similar to sinusoids in
  reptile hearts)
• Myocardial denervation
• Angiogenesis
• Does not increase blood flow acutely
• Increases blood flow after 2-6 months

Factor VIII antibody stain shows
endothelial-lined new blood vessels after 9
months Domkowski. Circulation 2001103469-71
32
Results from clinical trials of TMR

• 6 studies
• 86-275 patients
• HoYAG and CO2
• All show symptom improvement
• No study shows survival benefit

of patients with decrease of 2 CCS angina
classes
1.Allen NEJM 1999 2.Frazier NEJM 1999 3.Schofield
Lancet 1999 4.Burkhoff Lancet 1999 5.Aaberge JACC
2000 6.Jones Ann Thorac Surg 1999
33
Cost-utility analysis of TMR

• 188 patients randomized to medical management
  TMR
• Costs and survival data collected
• Mean year cost for TMR was 11,470 vs 2586 for
  medical management alone
• Survival 89 (TMR) vs 96 (medical) at 1 year
• Mean quality-adjusted life year difference was
  0.039 ( or 228,000 per QALY)
• Conclusion an inefficient use of resources for
  the United Kingdom

Campbell et al Eur J Cardiothorac Surg
200120312-8
34
Anesthetic implications of TMR

• Patients are sick
• Transesophageal echocardiography helpful (puff
  of smoke)
• Hybrid operations (CABG TMR) more common than
  TMR alone
• Cardiologists already hard at work perfecting
  percutaneous laser equipment!

35
Items for Discussion

• Newer techniques for coronary revascularization
• Off-pump coronary artery bypass (OPCAB)
• Total arterial grafting
• Minimally invasive techniques
• Transmyocardial laser revascularization
• Robotic surgery

36
Rationale for robot-assisted surgery

• Robot can accomplish surgery via smaller portal
  than with conventional minimally invasive
  techniques
• Further reduction in size of incision
• May ultimately provide opportunity for
  telesurgery where operator could be at long
  distance from patient

37
Challenges of robot-assisted surgery

• Limitations of convention suturing techniques
• Markedly increased time consumption
• Remarkable cost of robots (2-5M)
• Lack of demonstrated outcome benefit
• Challenge for surgeons learning a new technique

38
Anesthetic implications of robot-assisted surgery

• Markedly increased time consumption
• Positioning
• Padding
• Common need for one-lung anesthesia
• Double lumen tube
• Bronchial blocker
• Jet ventilation (alternative strategy)
• CO2 insufflation
• Mediastinal shift
• Hypercarbia

DAttelis J Cardiothorac Vasc Anesth
200216397-400 Dr. W Nifong. Personal
Communication
39
New approaches to cardiac surgeryAnesthetic
implications

• Cardiac surgery evolves rapidly, with or without
  data
• Emphasis on avoiding CPB may change as CPB
  apparatus improves
• Safety and utility of OPCAB vs CABG unclear
• Safety and utility of epidural remain
  controversial
• Robotic and minimally invasive techniques
  increasingly popular unclear outcome benefit
• Role of TMR unclear
• Intraoperative imaging consistently needed

40
OPCAB associates with reduced complications in
high-risk patients

• 286 OPCAB vs 1112 CABG CPB
• OPCAB older sicker (LVEFlt0.3 21 vs 9.6 renal
  disease 7 vs 2.3)
• 30-day mortality 3.5 vs 7

Al-Ruzzeh Eur J Cardiothorac Surg 20032350-5
41
Prospective RCT of thoracic epidural analgesia
for CABG
VAS Pain Score

• 80 randomized to TEA vs iv morphine (MS)
• VAS pain scale
• Better pain scores, less postoperative stress
  depression with TEA
• Improved PaO2 and peak expiratory flow rate with
  TEA

R at rest C cough
Postoperative Day
Royse. Ann Thorac Surg 20037593-100