The clinical impact of stress myocardial perfusion scintigraphy(MPS) and utilization of Appropriate use criteria (AUC): a tertiary care center experience

Introduction: To evaluate AUC for referral of cases for stress MPS and assess its clinical impact in further management.

Methods: We have retrospectively included 500 patients, who underwent stress MPS from January 2019 to December 2020. Demographic and clinical details were recorded and the 2009 American college of cardiology and American society of nuclear cardiology Appropriate use criteria (AUC) was used for assess the appropriateness of the study. The results were analyzed and the ability of stress MPS to lead to an impact in the cardio-vascular intervention was also evaluatedWe have retrospectively included 500 patients, who underwent stress MPS from January 2019 to December 2020. Demographic and clinical details were recorded and the 2009 American college of cardiology and American society of nuclear cardiology Appropriate use criteria (AUC) was used for assess the appropriateness of the study. The results were analyzed and the ability of stress MPS to lead to an impact in the cardio-vascular intervention was also evaluated

Results: A total of 500 patients, 294 male (58.8%) and 206 female (41.2%) with mean weight (kg) - 67.73 ± 14.43, mean height (cm) -162.34 ± 9.32 and mean BMI (Kg/m²) -25.72 ± 5.20 were included. Out of 500, 282 (56.4%) patients were referred for inducible ischemia and 218 (43.6%) for Pre-Anesthetic Clearance (PAC).

Past history of non-cardiac surgery in 25 (5.0%) patients and cardiac or vascular surgery in 81 (16.2%) patients.130 (26.0%) patients presented with chest pain. 93 (71.5%) out of 130 patients had typical anginal pain. 73.1% of male patients presented with typical anginal pain and 26.9% - atypical chest pain. 69.8% of female patients had typical anginal pain and 27.0% - atypical chest pain and 3.2% - non anginal chest pain. 28 (5.6%) patients had past history of MI.

Risk factors were hypertension in 329 (65.8%), diabetes in 167 (33.5%), obesity in 71 (14.2%), smoking in 84 (16.9%) and alcohol intake in 96 (19.2%). 418 (83.6%) patients were opted for adenosine stress, 5 (1.0%) for dobutamine stress and 77 (15.4%) patients for physiological TMT stress, metabolic equivalent of tasks (METS) score: <5 in 11 (2.2%), 5-8 in 43 (8.6%), 9-11 in 23 (4.6%) and >12 in 4 (0.8%) patients. Out of 91 patients, 14 (2.8%) patients had normal angiography and 77 (15.4%) patients had abnormal angiographic findings. 48 (9.7%) patients had previous history of PCI.

256 (51.2%) patients were categorized appropriate for stress MPS while 244 (48.8%) were categorized as inappropriate.

Risk factors more common in the appropriate AUC category: hypertension (75.8%), diabetes (39.6%), obesity (15.6%), smoking (17.6%), alcohol (23.8%), previous history of MI (8.2%) and past history of PCI (14.6%). MPS calculated LVEF was between 20-29 % in 10 (2.0%), 30-39 % in 27 (5.4%), 40-49 % in 38 (7.6%), 50-59 % in 37 (7.4%) and 60-69 % in rest 388 (77.6%) patients. Perfusion defect range 0-9 % in 66 (45.2%), 10-19 % in 34 (23.3%), 20-29 % in 26 (17.8%),30-39 % in 8 (5.5%), 40-49% in 6 (4.1%), 50-59% in 6 (4.1%) patients. 53 (10.6%) patients underwent an intervention in the form of PCI or CABG post MPS.

Chi-squared test for association between AUC Category and Post MPS intervention was significant (χ2 = 3.980, p = 0.046) with little strength of association between the two variables (Cramer's V) = 0.09. 13.3% patients in the appropriate AUC category had post MPS intervention in the form of PCI or CABG as compared to 7.8% patients in the inappropriate AUC category.

Conclusions: A significant number of patients presenting to our center of MPS were categorized as inappropriate for stress MPS.

Risk factors like hypertension, diabetes, obesity, smoking, alcohol intake, past history of MI and past history of PCI were more prevalent in the appropriate category as compared to the inappropriate category.

Although post MPS, a greater number of patients in the appropriate AUC category had intervention in the form of PCI or CABG. A significant patients deemed inappropriate as per AUC category saw a change in their clinical management.