Nuclear Cardiology MPS Clinical Application a brief review

Nuclear Cardiology (MPS) & Clinical Application a brief review V. R. Dabbagh Kakhki, M. D. Nuclear Medicine Specialist Associate Professor DSNMC Nuclear Medicine Research Center (NMRC; V. R. Dabbagh, DSNMC; www. DSNMC. ir MUMS)

Gated Myocardial Perfusion SPECT Most important clinical indications: Detection of CAD Risk stratification and prognosis of Pt’s with CAD Effectiveness of Therapy Viability Peri-operative risk assessment V. R. Dabbagh, DSNMC; www. DSNMC. ir

Risk and pre-test probability of CAD �There are different risk stratifications in patients with or without CAD. �Some risk stratifications for example: �Risk stratification in asymptomatic patients (based on risk of cardiac events in 10 years) �Pretest Probability of CAD for Symptomatic Patients �Risk assessment based on annual cardiac mortality rate V. R. Dabbagh, DSNMC; www. DSNMC. ir

Risk Stratification: asymptomatic � The ATP III report specifies absolute risk for CHD over the next 10 years. CHD risk refers to 10 -year risk for any hard cardiac event: � • CHD Risk � Low: � age-specific risk level that is below average. � a 10 -year absolute CHD risk less than 10%. � • Moderate: � age-specific risk level that is average or above average. � a 10 -year absolute CHD risk between 10% and 20%. � • High: � presence of diabetes mellitus in a patient 40 years of age or older, peripheral arterial disease or other coronary risk equivalent, � or a 10 -year absolute CHD risk of greater than 20%. �In FRS, cut-off values are %5 -20% V. R. Dabbagh, DSNMC; www. DSNMC. ir

Pretest Probability of CAD for Symptomatic (Ischemic Equivalent) Patients: �Once: presence of symptoms: pretest probability of CAD should be assessed. �There a number of risk algorithms available for example: �Very low � pretest probability: Less than 5% pretest probability of CAD �Low � pretest probability: Less than 10% pretest probability of CAD �Intermediate � pretest probability: Between 10% and 90% pretest probability of CAD �High � pretest probability: Greater than 90% pretest probability of CAD V. R. Dabbagh, DSNMC; www. DSNMC. ir

Pretest Probability of CAD for Symptomatic (Ischemic Equivalent) Patients: �There a number of risk algorithms available �Other algorithm: � low pretest probability: � < 20% pretest probability of CAD � Intermediate pretest probability: � 20% - 80% pretest probability of CAD � High pretest probability: � 80% < pretest probability of CAD V. R. Dabbagh, DSNMC; www. DSNMC. ir

Risk assessment �Based on annual cardiac mortality rate per year: �low risk: <1% �Intermediate risk : 1% to 3% �High risk: >3% V. R. Dabbagh, DSNMC; www. DSNMC. ir

Analysis Ø In addition to the qualitative evaluation: + apply a semi-quantitative segmental scoring system. • Standardizes the visual interpretation of scans • Global indices (summed scores, extent and severity). • Reproducible indices • Diagnostic and prognostic assessments V. R. Dabbagh, DSNMC; www. DSNMC. ir

20 -segment five point scoring system V. R. Dabbagh, DSNMC; www. DSNMC. ir

17 -segment five point scoring system V. R. Dabbagh, DSNMC; www. DSNMC. ir

Scoring: For each segment: Score 0 to 4 based on amount of tracer uptake. 0 1 2 Then: Stress phase: Summed all scores of all segments: SSS Rest Phase: Summed all scores of all segments; SRS V. R. Dabbagh, DSNMC; www. DSNMC. ir 3 4

Segmental Model Visual or Semi-quantitative analysis � 17 -segment five point scoring system � Summed Stress Score (SSS) � Summed Rest Score (SRS) � Summed Difference score (SDS) The myocardial segments may be roughly assigned coronary arterial territories. But there can be considerable variation among patients in the inferior and inferolateral segments of the LV due to the variable extent of the LCX and RCA territories.

Variability: • Apical segment : any of the three arteries. • LAD or RCA: Basal inferoseptal (3), mid-inferoseptal (9), and apical inferior (15) • RCA or LCX: Basal inferior (4), basal inferolateral (5), mid inferior (10), and mid-inferolateral (11) • LAD or LCX: mid-anterolateral • Although the greatest superposition in myocardial blood supply occurs in the inferolateral region corresponding to RCA and LCX territories, superposition of LAD and RCA territories also occurs at the level of inferoseptal region

Perfusion: Analysis If using a segmental model; the 17 -segment model and the associated nomenclature is recommended, as this model provides the best agreement with other imaging modalities such as MRI, echocardiography and anatomical data ASNC: the 17 -segment model is preferred � and the 20 -segment model should no longer be used V. R. Dabbagh, DSNMC; www. DSNMC. ir

Perfusion: Analysis �Risk groups may be defined by the �SSS: � <4 normal or nearly normal � 4 to 8 mildly abnormal � 9 to 13 moderately abnormal � > 13 severely abnormal V. R. Dabbagh, DSNMC; www. DSNMC. ir

ACC/AHA/ASNC Guidelines for the Clinical Use of Cardiac Radionuclide Imaging—Executive Summary A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines Circulation. 108: 1404 -1418 � V. R. Dabbagh, DSNMC; www. DSNMC. ir

Acute Syndromes �A: Patients+ Chest Pain: to the Emergency Department �B. Detection of AMI + Nondiagnostic Conventional Measures �C. Risk Assessment: Prognosis and Assessment of Therapy After STEMI �D. Risk Assessment: Prognosis and Assessment of Therapy After NSTEMI or UA V. R. Dabbagh, DSNMC; www. DSNMC. ir

A: Patients Presenting With Chest Pain to the Emergency Department �Decision for Pt: risk categories: UA, AMI and subsequent risk � 4 risk levels for CP: noncardiac, chronic SA, possible ACS, definite ACS �MPS: � Useful for diagnosis and management � most appropriate in patients with possible ACS. � High NPV for excluding ACS. V. R. Dabbagh, DSNMC; www. DSNMC. ir

A: Patients Presenting With Chest Pain to the Emergency Department Rest MPS: useful for identifying patients �high risk : perfusion defects: who should be admitted, �low risk: normal scans: who in general may be discharged with a low risk for subsequent ischemic events. V. R. Dabbagh, DSNMC; www. DSNMC. ir

A: Patients Presenting With Chest Pain to the Emergency Department V. R. Dabbagh, DSNMC; www. DSNMC. ir

B. Detection of AMI +Nondiagnostic Conventional Measures Rest MPS : �High sensitivity for diagnosing AMI. �Perfusion defects, however, do not distinguish among acute ischemia, acute infarction, or previous infarction. V. R. Dabbagh, DSNMC; www. DSNMC. ir

C: Risk Assessment: Prognosis and Assessment of Therapy After STEMI �Prognosis of STEMI is primarily a function of � EF � infarct size � residual myocardium at risk. �MPS: useful (information that is useful for immediate and long-term patient management) � LV function � assessing the presence and extent of stress-induced myocardial ischemia � Infarct size � Viable myocardium V. R. Dabbagh, DSNMC; www. DSNMC. ir

D. Risk Assessment: Prognosis and Assessment of Therapy After NSTEMI or UA - Early invasive strategy : any high-risk indicators + no serious comorbidities. - High-risk findings : eg, MPS markers - In the absence of high-risk findings: - either an early conservative or - early invasive strategy in patients without contraindications for revascularization. - MPS : useful in the predischarge risk stratification of patients with UA. - The presence and extent of reversible perfusion defects on stress testing after the patient is stabilized are highly predictive of future events. V. R. Dabbagh, DSNMC; www. DSNMC. ir

Chronic Syndromes V. R. Dabbagh, DSNMC; www. DSNMC. ir

Chronic Syndromes �A. Detection (Diagnosis) of Coronary Artery Disease MPS : most useful in patients with an intermediate likelihood of angiographically significant CAD on the basis of � age, sex, symptoms, risk factors, and the results of stress testing (for patients who have undergone prior stress testing). V. R. Dabbagh, DSNMC; www. DSNMC. ir

B. Management of Patients With Known or Suspected Chronic CAD: Assessment of Disease Severity, Risk Stratification, Prognosis � MPS: are best : for risk stratification in patients with a clinically intermediate risk of a subsequent cardiac event � Major prognostic factors: � measurements of stress-induced perfusion and function factors estimating the extent of LV dysfunction (LVEF, the extent of infarcted myocardium, TID , and increased lung uptake) are excellent predictors of cardiac mortality. V. R. Dabbagh, DSNMC; www. DSNMC. ir

B. Management of Patients With Known or Suspected Chronic CAD: Assessment of Disease Severity, Risk Stratification, Prognosis �Normal stress perfusion SPECT : : less than 1% annual risk of cardiac death or MI. � GSPECT: enhance its prognostic and diagnostic content. V. R. Dabbagh, DSNMC; www. DSNMC. ir

B. Management of Patients With Known or Suspected Chronic CAD: Assessment of Disease Severity, Risk Stratification, Prognosis � Frequency of Testing � develop new signs or symptoms suggesting a worsened clinical state, � In the absence of a change in clinical state, the estimated patient risk after initial testing (high, intermediate, or low, ) in individual recommendations. �Evaluation of the Effects of Medical Therapy � Although the available evidence suggests that the efficacy of therapy can be assessed with repeat SPECT procedures while the patient is under the effects of the medical treatment, information about the effects of medical therapy on outcomes is limited. V. R. Dabbagh, DSNMC; www. DSNMC. ir

C. Specific Patient Populations �Normal Resting ECG, Able to Exercise: �Multiple risk factors +with or without cardiac symptoms + normal resting ECG. � likely to : normal LV function and an excellent prognosis � a stepwise strategy is generally recommended: � Exercise ECG, and not a stress imaging procedure: initial test in: patients with an intermediate pretest likelihood of CAD � A stress imaging technique should be used for patients with widespread rest ST depression (more than 1 mm), complete left bundle-branch block (LBBB), ventricular-paced rhythm, preexcitation, or LVH with repolarization changes. V. R. Dabbagh, DSNMC; www. DSNMC. ir

C. Specific Patient Populations �Normal Resting ECG, Unable to Exercise: �an intermediate to high likelihood of CAD + normal resting ECG + unable to exercise: � pharmacologic MPS : highly effective in diagnosis and risk stratification. V. R. Dabbagh, DSNMC; www. DSNMC. ir

C. Specific Patient Populations �Patients With Nonspecific ST-T-Wave Changes: �such as might occur with digoxin, WPW �considered to have nondiagnostic stress ECG responses with regard to ST-segment depression. �intermediate to high likelihood of coronary disease can perhaps be effectively assessed for detection and risk stratification with MPS V. R. Dabbagh, DSNMC; www. DSNMC. ir

C. Specific Patient Populations �Asymptomatic Patients � Relatively low prevalence of CAD and risk of future events : Bayesian principles (ie, positive predictive value will usually be low). � Occupations may affect public safety (eg, airline pilots, truckers, bus drivers) or who are professional or high-profile athletes commonly undergo periodic exercise testing � Some asymptomatic patients, + high-risk clinical situation : testing may be appropriate (eg, diabetes or multiple risk factors). � Patients with a more than 20% 10 -year risk of developing coronary heart disease are considered to be at high risk in current National Cholesterol Education Program guidelines. V. R. Dabbagh, DSNMC; www. DSNMC. ir

C. Specific Patient Populations � After Coronary Calcium Screening: �score > 75 th percentile for age and sex, stress nuclear testing may sometimes be appropriate for purposes of risk stratification. V. R. Dabbagh, DSNMC; www. DSNMC. ir

C. Specific Patient Populations �Radionuclide Imaging before revascularization: �When: uncertainty : appropriate choice of therapy after coronary angiography : Stress MPI: risk stratify V. R. Dabbagh, DSNMC; www. DSNMC. ir

C. Specific Patient Populations �Radionuclide Imaging After PCI : �Symptom status : unreliable index of development of restenosis, : 25% of asymptomatic patients : having ischemia on exercise testing. �MPS: helpful V. R. Dabbagh, DSNMC; www. DSNMC. ir

C. Specific Patient Populations �MPS After CABG : �Useful in determining the location, extent, and severity of ischemia. �Prognostic value V. R. Dabbagh, DSNMC; www. DSNMC. ir

C. Specific Patient Populations �MPS Before Noncardiac Surgery: �noninvasive preoperative testing is best : � at intermediate clinical risk (diabetes, stable CAD, compensated heart failure) + intermediate- or high-risk surgery. �Exercise stress is preferred in patients capable of achieving adequate workloads; �Radionuclide techniques: � baseline ECGs render exercise interpretation invalid � inability to exercise. V. R. Dabbagh, DSNMC; www. DSNMC. ir

C. Specific Patient Populations �MPS Before Noncardiac Surgery: �MPS: High NPV �Patients with reversible defects are at greater risk for perioperative ischemia than are those with fixed defects; V. R. Dabbagh, DSNMC; www. DSNMC. ir

C. Specific Patient Populations �Heart Failure: � MPI: � Ischemic o nonischemic cardiomyopathy � Viability in CAD � Copresence of CAD (class IIa) V. R. Dabbagh, DSNMC; www. DSNMC. ir

V. R. Dabbagh, DSNMC; www. DSNMC. ir

Prognostic value of Myocardial Perfusion SPECT V. R. Dabbagh, DSNMC; www. DSNMC. ir

�Old studies: Focus on detection of stenosis mainly with anatomic imaging modalities. �The current paradigm in disease management is of a riskbased approach. �Therefore the main task of imaging is to define patient risk. �MPS: �Diagnostic: Most effective: intermediate likelihood of CAD �Prognosis: High likelihood of CAD �In the presence of a normal stress myocardial perfusion scan, exercise ECG had no added prognostic value V. R. Dabbagh, DSNMC; www. DSNMC. ir

Total ischemic burden &Risk V. R. Dabbagh, DSNMC; www. DSNMC. ir Circulation ; 1998; 535 -43

Warranty period for a normal MPI �Warranty period = The length of time that patients remain at low risk after the normal MPS. (Time to 1% risk) �Normally: 1. 5 -2 yrs (up to 5 yrs in stable patients) �Uniform with time in Pts without known CAD. �In patients with known CAD, risk increased with time J Am Coll Cardiol 2003: 1329– 40 Circ Cardiovasc Imaging. 2010: 520 -526 V. R. Dabbagh, DSNMC; www. DSNMC. ir

�GSPECT is the best modality for prognostic �Normal MPI SPECT means low risk irrespective of results of other modalities. V. R. Dabbagh, DSNMC; www. DSNMC. ir

V. R. Dabbagh, DSNMC; www. DSNMC. ir

SCREENING DM , MS • CCS>100: aggressive medical therapy with target LDL , 70 and the target blood pressure would be 120/80 V. R. Dabbagh, DSNMC; www. DSNMC. ir

V. R. Dabbagh, DSNMC; www. DSNMC. ir

Elder : CCS>400: high frequency; dense CAC; : CCS and MPS V. R. Dabbagh, DSNMC; www. DSNMC. ir

Possible Future Algorithms �Screening: CAC: � men >45 women>55 V. R. Dabbagh, DSNMC; www. DSNMC. ir

V. R. Dabba gh; DSNMC; www. DSN MC. ir