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Toronto Notes 2019 Ischemic Heart Disease
Operative Issues
• leftventricular(LV)functionisanimportantdeterminantofoutcomeofallheartdiseases
• patientswithsevereLVdysfunctionusuallyhavepoorprognosis,butsurgerycansometimes
dramatically improve LV function
• assessviabilityofnon-functioningmyocardialsegmentsinpatientswithsignificantLVdysfunction
using delayed thallium myocardial imaging, stress echocardiography, PET scanning, or MRI
CABG and Antiplatelet Regimens
• refertoCCSguidelines–2012updateonantiplatelettherapy–formoreinformationifpossible
• prior to CABG, clopidogrel, and ticagrelor should be discontinued for 5 d and prasugrel for 7 d before
surgery
• dualantiplatelettherapyshouldbecontinuedfor12moinpatientswithACSwithin48-72hafter
CABG
• ASA(81mg)continuedindefinitely(canbestarted6haftersurgery)
• patients requiring CABG after PCI should continue their dual antiplatelet therapy as recommended in
the post-PCI guidelines
Table 12. Risk Factors for CABG Mortality and Morbidity (decreasing order of significance)
Cardiology and Cardiac Surgery C33
Risk Factors for CABG Mortality
Urgency of surgery (emergent or urgent) Reoperation
Older age
Poor left ventricular function (see below) Female gender
Left main disease
Others include catastrophic conditions (cardiogenic shock, ventricular septal rupture, ongoing CPR), dialysis-dependent renal failure, end-stage COPD, DM, cerebrovascular disease, and peripheral vascular disease
Procedural Complications
Risk Factors for CABG Post-Operative Morbidity or Increased Length of Stay
Reoperation
Emergent procedure
Pre-operative intra-aortic balloon pump (IABP) CHF
CABG + valve surgery
Older age
Renal dysfunction
COPD
DM
Cerebrovascular disease
Safety and Efficacy of Drug-Eluting and Bare Metal Stents
Circulation 2009;119;3198-3206
Study: Meta-analysis of RCTs and observational studies. 22 RCTs and 34 observational studies. Population: 9,470 and 182,901 patients in RCTs and observational studies respectively who underwent percutaneous coronary intervention. Intervention: Drug-Eluting Stents (DES) versus Bare Metal Stents (BMS).
Outcome: All-cause mortality, myocardial infarction (MI), and target vessel revascularization (TVR). Results: No difference in mortality was found between DES vs. BMS by RCTs, while observational studies showed significantly lower mortality rates in DES-treated patients (hazard ratio (HR) 0.78, p<0.001). No difference in MI incidence was found in RCTs, while lower incidences of MI were found in observational studies (HR 0.87, p=0.014). DES has a significantly lower TVR rate in both RCT (HR 0.45, p<0.001) and observational studies (HR 0.46, p<0.001).
Conclusions: DES significantly reduces rates of TVR compared to BMS. Although there is no difference in mortality or MI incidence as found by RCTs, observational studies suggest lowered mortality and MI rates in patients with DES over BMS.
• CABGusingcardiopulmonarybypass(CPB)
■ stroke and neurocognitive defects (microembolization of gaseous and particulate matter) ■ immunosuppression
■ systemic inflammatory response leading to:
◆ myocardial dysfunction ◆ renal dysfunction
◆ neurological injury
◆ respiratory dysfunction ◆ coagulopathies
OFF-PUMP CORONARY ARTERY BYPASS SURGERY
Procedure
• avoidstheuseofCPBbyallowingsurgeonstooperateonabeatingheart
■ stabilization devices (e.g. Genzyme Immobilizer®) hold heart in place allowing operation while
positioning devices (Medtronic Octopus® and Starfish® system) allow the surgeon to lift the beating
heart to access the lateral and posterior vessels
■ procedure is safe and well tolerated by most patients; however, this surgery remains technically
more demanding
Indications
• usedinpoorcandidatesforCPBwhohave:calcifiedaorta,poorLVEF,severeperipheralvascular disease (PVD), severe COPD, chronic renal failure, coagulopathy, transfusion objections (e.g. Jehovah’s Witness), good target vessels, anterior/lateral wall revascularization, target revascularization in older, sicker patients
• absolutecontraindications:hemodynamicinstability,poorqualitytargetvesselsincluding intramyocardial vessels, diffusely diseased vessels, and calcified coronary vessels
• relativecontraindications:cardiomegaly/CHF,criticalleftmaindisease,smalldistaltargets,recentor current acute MI, cardiogenic shock, LVEF <35%
Outcomes
• OPCABdecreasesin-hospitalmorbidity(decreasedincidenceofchestinfection,inotropicrequirement, supraventricular arrhythmia), blood product transfusion, ICU stay, length of hospitalization, and CK- MB and troponin I levels
• nosignificantdifferenceintermsofsurvivalat2yr,frequencyofcardiacevents(MI,PCI,CHF, recurrent angina, redo CABG), or medication usage compared to on-pump CABG