Lexiscan Test Results: SSS 3, SRS 3, SDS 0
Interpretation
Your Lexiscan test shows minimal fixed perfusion abnormality without reversible ischemia, indicating a small area of prior myocardial damage (scar) but no active, flow-limiting coronary artery disease causing current ischemia. 1
Understanding the Scores
What Each Score Means
Sum Stress Score (SSS) of 3 indicates minimal perfusion abnormality detected during pharmacological stress with regadenoson, representing approximately 3% of the left ventricular myocardium 1
Sum Rest Score (SRS) of 3 shows the same minimal perfusion abnormality is present at rest, suggesting this represents fixed scar tissue rather than reversible ischemia 1
Sum Difference Score (SDS) of 0 (calculated as SSS minus SRS) confirms there is no reversible ischemia, as the perfusion defect does not worsen with stress 1, 2
Clinical Significance
An SSS ≤3 is generally considered within normal limits or minimally abnormal, and does not meet the threshold for hemodynamically significant coronary artery disease 1
The absence of reversible ischemia (SDS = 0) means no coronary territories demonstrate stress-induced perfusion defects that would indicate flow-limiting stenosis 1
Fixed defects (SRS = SSS) typically represent prior myocardial infarction or scar tissue, though small fixed defects can occasionally represent imaging artifacts 3
Prognostic Implications
Patients with SSS ≤3 have excellent prognosis with annual cardiac event rates <1%, similar to those with completely normal scans 3
The absence of inducible ischemia (SDS = 0) indicates low risk for perioperative cardiac events if noncardiac surgery is being considered 3
Fixed defects predict long-term cardiac events more than perioperative events, reflecting underlying coronary artery disease rather than acute ischemic risk 3
Clinical Management Recommendations
Immediate Actions
Continue optimal medical therapy including aspirin, statin therapy, blood pressure control, and diabetes management if applicable, as the test confirms presence of coronary atherosclerosis (evidenced by the fixed defect) 3
No urgent invasive coronary angiography is indicated based on these results, as there is no evidence of hemodynamically significant ischemia 3
Risk Factor Modification
Aggressive lipid management with statin therapy has been shown to improve myocardial perfusion even in patients with minimal perfusion abnormalities 4
Address all modifiable cardiovascular risk factors including smoking cessation, weight management, and exercise as tolerated 3
Follow-Up Strategy
Repeat stress testing is not routinely indicated unless symptoms develop or change significantly 3
If symptoms persist despite negative ischemia testing, consider alternative diagnoses for chest pain or dyspnea 3
Important Caveats
Potential Limitations
"Balanced ischemia" can produce false-negative results when severe multivessel or left main disease causes globally reduced perfusion that appears homogeneous on imaging 5
If clinical suspicion remains high despite these results (particularly with ongoing typical anginal symptoms), consider coronary CT angiography with FFR-CT to evaluate for anatomic disease 5
Small fixed defects (SSS = 3) may occasionally represent attenuation artifacts rather than true scar, particularly in women (breast attenuation) or obese patients (diaphragmatic attenuation) 3
When to Reconsider the Results
Persistent typical anginal symptoms despite negative ischemia testing warrant further evaluation 3
Patients with multiple high-risk features (diabetes, strong family history, multiple risk factors) may benefit from anatomic imaging even with minimal perfusion abnormalities 3
Elderly patients or those with diabetes may have microvascular dysfunction causing symptoms without epicardial stenosis 1, 4