Prognostic value of MPI S.R.Zakavi,MD.IBNM Nuclear Medicine Research Center, Mashhad University of Medical Sciences Mashhad, Iran

Introduction: Previous studies: Sensitivity, specificity and accuracy of MPI. The current paradigm in disease management is of a risk-based approach. Therefore the main task of imaging is to define patient risk. Proper risk stratification is also critical for the management of patients with known or suspected CAD.

Definition of end points Hard events defined as cardiac death and myocardial infarction Soft events defined as incidence of unstable angina and PCI procedures

Risk categorization The ATP III report specifies absolute risk for CHD over the next 10 years for any hard cardiac event. CHD Risk—Low : <10% CHD Risk—Moderate :(10-20%) CHD Risk—High : >20%) NIH Publication No ; 2002

Quantification Visual scoring

Quantification of defects Score can theoretically be ranged from 0 to 68

Scoring in MPI Summed stress score (SSS) Summed rest score (SRS) Summed difference score(SDS) SDS=SSS-SRS % of LV involvement= Score/68 For example if SSS=13 it means that 13/68 or 19.1% of LV is involved.

SSS values SSS<4, SSS≤3 (<4-6% of LV) Low risk :SSS=4-8 (9) Moderate risk: SSS= (13) High risk: SSS>12 (13)

Beyond visual estimation QPS (From Cedars-Sinai, LA) ECT b (From Emory Univ. Atlanta) 4DM SPECT (University of Michigan) LMC, Multidim,… *Significant difference between different software. *Accuracy is slightly better for QPS compared to others. *Manual correction is more frequently needed with ECT b *Serial images should be processed by a single soft ware. J Nucl Cardiol 2008;15: 27-34

QPS

QGS

Introduction: The size, severity, and reversibility of the defect implies the extent of risk, or the ‘‘total ischemic burden”. Circulation ; 1998;535-43

Circulation. 1996;905–914 MPI Vs Duke treadmill score

MPI Vs CAG J-ACCESS Eur J Nucl Med Mol Imaging 2009:1329–1337

High risk criteria for future events Extent and severity of inducible ischemia. Increased lung uptake of thallium. Stress-induced ventricular dilatation (TID). Depressed LV ejection fraction after stress(stunning) Increased RV uptake

Appropriate Use Criteria (AUC)

Revascularization Vs Medical therapy Circulation. 2003:

Pre-operative assessment before Non-cardiac surgery Patients with noncardiac revascularization had strong likelihood of coexistence CAD Generally not a good candidate for ETT. In a Meta-analysis of 3,718 patients the PPV of inducible ischaemia for peri-operative death or MI was 12.9% compared with a NPV of 98.6%, a risk ratio of 9.1. J Am Coll Cardiol 2002: 542–553

Pre-operative risk assessment before Non-cardiac surgery

AUC J. Am. Coll. Cardiol. 2009;

In ACS & after ACS Risk stratification in patients awaiting serum troponin estimation.(NPV>99%) 451 patients with AMI were studied with Dip- MIBI, 2-4 days or predischarge Ex.MIBI. Multivariate predictors of in-hospital cardiac events: SSS, SDS & pCK For postdischarge cardiac events, multivariate predictors was: SSS, SRS, SDS and ANT MI. Circulation. 1999:

AUC After ACS

What is the risk of a Normal MPI?

Normal stress MPI In Pts with normal 201 Tl MPI from 16 studies, followed for a mean of 28.3 months, the death or non-fatal MI rate averaged about 0.7% /year. In pts from 14 studies with 99m Tc-MIBI, Hard event rate was 0.6%. 99m Tc-Tetrofosmin was equally effective in prognostic stratification. Circulation 2003; J Am Coll Cardiol 1998; J Nucl Med 2003 ; 648

Normal stress MPI In the presence of a normal stress myocardial perfusion scan, exercise ECG had no added prognostic value. If patients had not reached 85% of MHR, the risk was slightly higher.(Underlying disease) In patients with known CAD, the risk was slightly higher (0.9% Vs 0.2%). Pharmacologic stress; (Adenosine: 1.6%, controversies). J Am Coll Cardiol 1998; J Am Coll Cardiol 2003; Am J cardiol 1997; Am J cardiol 2000; Circulation ; 1996;

How long a MPI result is valid? Warranty period

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: yrs Parametric survival models revealed that in patients without previous CAD the level of risk was uniform with time. In patients with known CAD, risk increased with time (e.g., risk in the first year was less than in the second year, hence, a dynamic temporal component of risk was present). J Am Coll Cardiol 2003: 1329–40 Circ Cardiovasc Imaging.2010:

When the repeat imaging is indicated?

AUC J. Am. Coll. Cardiol. 2009;

In elderly 5200 elderly(>75 years old) patients underwent GSPECT (Dual isotope) Followed for 2.8±1.7yrs- (860 followed 6.2±2.9yrs) Circulation.2009:

In women In a study of 3,402 women, normal MPS predicted a favorable outcome and the extent of inducible ischaemia was strongly associated with mortality. The cardiac mortality rate in women is higher than men, both in diabetic and nondiabetic groups. No sex difference in MPI prediction of cardiac events. Am J Med 1999: 172–178 Q J Nucl Med Mol Imaging 2005: 72-80

In patients with CKD CKD is also associated with a higher incidence of cardiac events and poorer survival 820 patients with GFR of <60 ml/min per 1.73 m 2 Eur J Nucl Med Mol Imaging 2009:1835–1841

Conclusion GSPECT is the best modality for prognostic stratification(better than CAG, DTS, clinical information,…) Normal MPI SPECT means low risk irrespective of results of other modalities. Risk stratification is valid in different clinical conditions (elderly, diabetics, women, CKD,….)

Shamkhal - Near Mashhad