Anesthetic implications of cardiovascular disease

1. Anesthetic implications of cardiovascular disease

2. objectives • To identify the patients at risk for peri-op cardiac complications. • To evaluate the severity of underlying ds and if necessary implement measures to prepare high risk patients for non-cardiac surgery with maximum optimisation. • Identification of risk factors • Preparation and plan of anaesthetic management intraoperatively. • Postoperative management of adverse events (stress on prevention).

3. Pre operative evaluation • History (including risk stratification) • Examination • Laboratory investigations • Cardiac function assessment • Cardiovascular conditions assoc: hypertension, ischemic heart disease, heart failure, valvular heart disease, arrythmias, peripheral vascular disease, pulmonary arterial hypertension.

4. history • Detailed history of cardiovascular co morbidity (symptoms, duration, past interventions etc.) • Other co existing conditions (DM, PVD) • Medications – history, current medication, effectiveness. • History of any aggravating and relieving factors. • Asthma, epilepsy, drug allergy, egg allergy, past surgery- type of anesthesia, any event, post op complication. • Loose tooth, denture.

5. examination • Vital parametes : pulse rate, volume, nature, bruit, peripheral pulses. BP, in all limbs in PVD. • GPE – pallor, cyanosis, JVP, Pedal edema. • CVS examination- displaced apical impulse, parasternal heave, thrill, palpable P2, S3, S4, murmurs. • Resp examination – b/l air entry, added sounds, pulmonary edema, pleural effusion. • Abd examination – signs of HF • Airway assessment. • Peripheral venous access • Spine examination.

6. Lab evaluation • CHG – Hb, TLC,DLC, Hct, platelet count. (anemia adversely affects cardiac outcome; Hb >10 gm% a/w less morbidity) • FBS • LFT,RFT with electrolytes(BUN and Cr esp in HTN, diuretics) • URINE-routine and microscopy. • CULTURES in I/E. • CXR (Cardiomegaly, Signs of LV dysfn- incrsdpul vascular markings, pul edema, pleural effusion, Pacemaker, ICD can be seen, evidence of PAH) • ECG (baseline, within last 3 months if no new symptoms, 12 lead ECG, CAD- in old MI ,inverted t-wave, prominent and deep Q-wave, dysrhythmias, Conduction defects, Digitalis toxicity, dyselectrolytemia). • Coagulation profile (esp in patients of valvular disease on anticoagulants).

7. Pre operative 12 lead ecg • recommended for patients with at least one clinical risk factor for vascular surgical procedures; for patients with known CHF, peripheral arterial disease, or cerebrovascular disease undergoing intermediate-risk surgical procedures. • reasonable in persons with no clinical risk factors for vascular surgical procedures • may be reasonable in patients with at least one clinical risk factor for intermediate-risk operative procedures • not indicated for asymptomatic persons undergoing low-risk surgical procedures.

8. Presence ,severity & reversibility of CAD 1) risk factors 2) active cardiac condition 3) previous MI, prior cardiac evaluation 4) past interventions – CABG,PTCA 5) functional capacity (NYHA) 6) co-morbid conditions 7) dysrhythmias

9. Identification of risk factors • Physical status classification(ASA) • Cardiac risk index ( Goldman) • Revised cardiac risk index ( Lee’s ) • Eagle criteria • ACC/AHA guidelines 2007

10. Goldman Cardiac risk index • Third heart sound (S3): 11 pts • Elevated jugulovenouspressure: 11 pts •  Myocardial infarction in past 6 months: 10 pts •  ECG: premature arterial contractions or any rhythm other than sinus: 7 pts •  ECG shows >5 premature ventricular contractions per minute: 7 pts •  Age >70 years: 5 pts •  Emergency procedure: 4 pts •  Intra-thoracic, intra-abdominal or aortic surgery: 3 pts •  Poor general status, metabolic or bedridden: 3 pts

11. Lee’s revised index (simple index) • High risk surgery (intraperitoneal, intrathoracic, or suprainguinal vascular procedures) • H/O Ischemic heart disease (any diagnostic criteria) • H/O Heart failure • H/O Cerebro-vascular disease • Diabetes mellitus req treatment with insulin • Pre-op S.Crover 2 mg/dl Rate of major cardiac complications- 0 – 0.5 % 1- 1.3% 2 – 4% >3 – 9 %

12. Risk stratification of surgery High (>5%) • - Emergency major operations, particularly in elderly • - Aortic and major vascular procedures • - Peripheral vascular procedures • - Prolonged procedures with large fluid shifts +/- blood loss Intermediate (<5%) • - Intraperitoneal / Intrathoracic surgery • - Carotid endarterectomy - Head and neck surgery • - Orthopedic surgery - Prostate surgery Low (<1%) • - Endoscopic procedures - Superficial procedures • - Cataract surgery - Breast surgery

13. Eagle criteria • Similar to Goldman's but specifically for evaluating cardiac risk in vascular surgery patients • " Eagle factors": >70yo, h/o angina, significant Q's, CHF, DM needing Rx • Risk of perioperativeMI: "Low risk": if 0 factors, risk = 3.1%; no additional pre-op testing needed "Intermediate risk: if 1-2 factors, risk = 15%; noninvasive testing with angio if inducible ischemia. "High risk: if > 2 factors, risk = 50%; go straight to angiography. • If angio shows left main disease etc., consider angioplasty or CABG before planned surgery; if serious lesions not amenable to either, consider foregoing surgery.

15. ACC/AHA guidelines

16. ACC/AHA guidelines • STEP 1:determine the urgency of the surgery; focus on perioperative surveillance (serial ECGs, enzymes, monitoring) and risk reduction. • STEP 2:determine whether the patient has an active cardiac condition (acute MI, unstable or severe angina, decompensated heart failure, severe valvulardisease, arrhythmias) which requires postponement. acute MI(in 7 days) considered high risk and elective surgeries postponed. A recentMI (within the past 30 days) with evidence of myocardium at risk (generally based on persistent symptoms or results of stress testing), is also a high-risk condition. However, a recent (8 to 30 days previously) MI without evidence of myocardium at risk is considered an active cardiac condition and equivalent to any history of CAD.

17. STEP 3:determination of the surgical risk or severity. Patients without active cardiac conditions who are undergoing low-risk surgery can proceed to surgery without further cardiac testing. • STEP 4: assesses the patient's functional capacity. Asymptomatic patients who are highly functional can proceed to surgery. • STEP 5: determination for patients with poor or indeterminate functional capacity. The presence and number of clinical predictors drive the recommendations for and probable benefit of further cardiac testing. Patients with no clinical predictors proceed to surgery.

18. Clinical predictors • MAJOR- acute or recent MI, UA, decompensated CCF, significant arrythmias ,severe valvular heart disease. • INTERMEDIATE- mild Angina ,old MI(more than 1 mnth), insulin dependent diabetes, compensated CCF, pre-op creatinine >2mg% • MINOR- abnormal ECG, cardiac rhythm abnormality, history of stroke, uncontrolled HTN, low functional capacity

19. Cardiac testing • Resting & ambulatory ECG • Exercise stress testing • Echocardiography • Pharmacologic stress testing Dipyridamole/adenosine thallium scintigraphy Dobutamine echocardiography • Coronary angiography

20. RESTING ECHO: to detect presence & significance of valvularheart ds,to detect CHD, LVEF, chamber enlargement & hypertrophy • RWMA – types & location: the assessment of resting LV fxn not routinely recommended for preopscreening. • Predictive value • LVEF <35% leads to postop CHF • No consistent correlation with postopischemia • Indicated in Poorly controlled CHF, Unknown systolic or diastolic function in valvular heart ds, long standing uncontrolled HTN.

21. STRESS TESTING: Exercise stress alone (usually Bruce protocol),Exercise / pharmacological stress with nuclear myocardial perfusion imaging (MPI), stress echo (Pharmacologic or exercise). • Exercise stress echo: • INDICATIONS- prior non diagnostic or if likelihood of false positive ECG stress test, ECG abnormalities making interpretation of ECG stress testing difficult, for prognostic information post MI, to determine success of intervention . • Images are obtained once pt hs achieved 85% of target HR (220-age) to see wall motion abn during max workload and lastly recovery images with in 90 sec of peak HR. Pharm stress echo: Unable to exercise or Inability to achieve target heart rate during exercise because of therapy with High dose beta-blocker or calcium channel blocker • Dobutamine/dipyridamole/adenosine used to induce cardiac stress.

22. Contraindications for stress testing • Acute myocardial infarction (within two days) • Unstable angina pectoris • Uncontrolled arrhythmias causing symptoms of hemodynamic compromise • Symptomatic severe aortic stenosis • Uncontrolled symptomatic heart failure • Active endocarditis or acute myocarditis or pericarditis • Acute aortic dissection • Acute pulmonary or systemic embolism • Acute noncardiac disorders that may affect exercise performance or may be aggravated by exercise

23. Coronary angiography • INDICATIONS - Done in Pts having positive stress tests suggesting significant myocardium at risk. -To detect or exclude serious CAD i.e. left main or 3 vsds. -chronic stable angina pts who are severely symptomatic despite medical therapy -Pts with ventricular dysfxn -In young patients with VHD to rule out assoc. CAD before cardiac surgery. -patients being considered for revascularization -Helps to decide how many bypass grafts should be performed - for definitive diagnosis of CAD individuals whose occupations could place others life in danger( pilots)

24. Pre operative optimisation • Generally patients are on multiple drugs depending on the cardiovascular condition: antihypertensives, diuretics, beta blockers, digoxin, vasodilators, anticoagulants. • HYPERTENSION: elective surgery be delayed if BP>180/110 mm Hg. If severe end organ damage is present, the goal should be to normalize BP as much as possible before surgery. Effective lowering of risk may require 6-8 weeks of therapy to allow regression of vascular and endothelial changes. If surgery can’t be postponed, the goal is not to decrease chronically increased BP too rapidly, as too rapid lowering of BP may increase risk of cerebral, coronary ischemia. • Rule out causes such as coarctation, hyperthyroidism, pheochromocytoma, or drug use such as cocaine, amphetamines, anabolic steroids.

25. routinely administer all antihypertensive drugs preoperatively, except ACE inhibitors or angiotensin II antagonists , which is tailored to the individual patient, due to risk of intra operative hypotension. • If these drugs are continued, vasopressin is the drug of choice for refractory hypotension. • the major effect of diuretics after 1 week of therapy is arteriolar vasodilation and assessment of urine output may be inaccurate if the diuretic is abruptly discontinued on the morning of surgery, so some studies advocate continuing them, rule out and correct dyselectrolytemias. • Beta blockers must be continued in all patients (if on therapy). No evidence in favour of acute administration of these drugs though some studies have shown benefit with low doses. • No role of prophylactic NTG unless ischemia occurs. • Optimal anxiolysis.

26. IHD/ CAD: Vasodilationwith nitroglycerine, nitroprusside, prazosin in order to decrease ventricular wall tension. Allaying fear, anxiety and pain preoperatively are desirable goals in patients with CAD to prevents sympathetic activation, which affects myocardial oxygen supply–demand balance. To continue beta blockers (dosages adjusted to achieve an HR lower than 70 beats/min)statins, antihypertensivesshould be continued. • PCI performed “to get the patient through surgery” may not improve perioperative outcome because cardiac complications may not occur in patients with stable or asymptomatic coronary stenosis. • elective noncardiac surgery after PCI, with or bare metal stent placement, should be delayed for 4 to 6 weeks; with drug eluting stent for 1 year.

27. Continue aspirin therapy in all patients with a coronary stent and discontinue clopidogrel for as short an interval as possible for patients with bare-metal stents in place for less than 30 days or drug-eluting stents for less than 1 year. • Aspirin (75-150 mg/day) for primary prev: Stop 7 days before operation as needed. • Secondary prevention: stop if Risk of bleeding in closed space (intracranial neurosurgery, intra-medullary canal surgery, posterior eye chamber ophthalmic surgery). • Aspirin+clopidogrel: High-risk situations:<6 weeks after MI, PCI, BMS, stroke,<12 months after DES,High-risk stents stop clopidogrel only if above surgery else continue both. • Low risk: Stop clopidogrel, Maintain aspirin. • the risk/benefit ratio of upholding vs withdrawing aspirin must be evaluated for each case individually; in case of aspirin upholding, early postoperative re-institution is important.

28. HEART FAILURE: may be systolic, diastolic or both. Hypertension is a cause of diastolic dysfunction, and LVH on an ECG should raise suspicion. Ischemic heart disease is the most common cause of systolic dysfunction. • Decompensated heart failure is considered a high-risk cardiac condition, and elective surgery should be postponed . Brain naturetic peptide (BNP),released from the ventricles of the heart, useful in evaluation. plasma concentration of BNP correlates with NYHA functional class. • Digoxin levels should not be routinely measured unless toxicity under treatment or noncompliance is suspected. One should determine trough levels of digoxin. • An objective measure of LVEF, ventricular performance, and diastolic function with echocardiography is helpful.

29. VALVULAR HEART DISEASE: Murmurs: D/t turbulent flow across the defective valve. Note the character, location, intensity, direction of radiation.Systolicmurmurs: AS, PS or MR,TR. Diastolic murmurs: MS, TS or AR, PR. Dysrhythmias: AF (esp Mitral valve ds.) i.e. with enlarged Lt atria. Predisposed to thromboembolic phenomenon. benign murmurs occur with high-outflow states such as hyperthyroidism, pregnancy, or anemia. • stenotic lesions progress faster than regurgitant lesions do. • Regurgitant lesions tolerated better. • If on anticoagulants target INR<1.5. in case of high risk pts consider bridging therapy with heparin. Weigh risk vs benefit for regional anaesthesia(spinal haematoma, stenotic lesions). • Prophylaxis of Bacterial endocarditis

30. ACC/AHA Guidelines: Echocardiography in Asymptomatic Patients with Cardiac Murmurs • Class I—echocardiography is useful in asymptomatic patients with the following cardiac murmurs: • Diastolic murmurs • Continuous murmurs • Late systolic murmurs • Murmurs associated with ejection clicks • Murmurs that radiate to the neck or back • Grade 3 or louder systolic murmurs • Class IIa—in asymptomatic patients with: • Murmurs associated with other abnormal physical findings on cardiac examination • Murmurs associated with an abnormal ECG or CXR • Class III—echocardiography is not useful in asymptomatic patients with the following murmurs: • Grade 2 or softer midsystolic murmurs considered innocent or functional by an experienced observer.

31. Assessment of Prosthetic Valve function: • Dysfunction (Change in intensity/ quality of clicks, new or change in characteristics of murmurs) • Tranthoracic Echo: To assess ring stability and leaflet motion • Transesophageal Echo: Better resolution • MRI: For prosthetic valve regurg, paravalvular leak • Cardiac Catheterisation: For Transvalvular pressure gradient, Effective valve area

32. ARRYTHMIAS: Bradyarrhythmias, especially if profound or associated with dizziness or syncope, are generally managed with pacemakers. • Predictors of the need for pacing included previous symptomatic bradyarrhythmia, a history of transient complete AV block, and aortic valve disease. • More than five PVCs per minute on preoperative examination correlates with perioperative cardiac morbidity.the classic criteria for treating PVCs: the presence of R-on-T couplets, the occurrence of more than three PVCs per minute, and multifocality of PVCs, must be added frequent (>10/hr over a 24-hour period) and repetitive ventricular beats. • Premature atrial contractions and cardiac rhythm other than sinus also correlate with perioperative cardiac morbidity. • Preoperative evaluation focuses on reversible causes such as hypokalemia, ischemia, acidosis, hypomagnesemia, drug toxicity, and endocrine dysfunctionand their correction.

33. ventricular arrhythmias classification: • Benign: isolated ventricular premature beats (VPBs) without heart disease No need for further evaluation No risk of sudden cardiac arrest • Potentially lethal: greater than 30 VPBs/hr or nonsustained ventricular tachycardia with underlying heart disease Requires cardiology evaluation with possible echocardiography, stress testing, catheterization, or electrophysiologic testing Moderately high risk of sudden cardiac arrest; may benefit from an ICD • Lethal: sustained ventricular tachycardia, ventricular fibrillation), syncope, or hemodynamic compromise associated with VPBs with underlying heart disease and often depressed cardiac function. Requires cardiology evaluation with possible stress testing, echocardiography, catheterization, or electrophysiologic testing High risk of sudden cardiac arrest; likely to benefit from an ICD.

34. Intra operative management • Adequate premedication: avoids sympathetic response. • Technique of anesthesia: general vs regional. • Regional avoids airway manipulation but in an unco operative patient anxiety can stimulate tachycardia and angina like symptoms. If planned for hypotensiveanaesthesia, better managed with GA. • Monitoring: ECG remains the standard to monitor for ischemia, a display monitor that allows viewing of two ECG leads simultaneously, usually leads II and V5, along with automated ST-segment analysis. • NIBP , pulse oximetry essential. • IBP to be weighed as per surgery. • PA catheter, TEE. • Intake/output monitoring • NMJ monitoring

35. Most opioids, hypnotics, and volatile anesthetics have been used successfully in different combinations for induction and maintenance of anesthesia. Anesthetic drugs and doses are selected according to two main considerations, the first being LV function. • patients may require vasopressor or inotropic pharmacologic support. • observation for normothermia, absence of excessive bleeding or documented coagulopathy, and acceptable urine output, blood gases, and hematocrit. • Avoidance of histamine releasing drugs.

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