QUESTION: is nuclear myocardial perfusion scintigraphy useful in predicting an increase in exercise capacity after coronary artery revascularization using percutaneous coronary intervention (PCI)?
BACKGROUND: The Courage Trial found a lack of survival benefit to percutaneous coronary intervention as compared to optimum medical therapy alone. However, in some patient subgroups, PCI was shown to have important quality of life benefits. Thus, there continues to remain doubt over who should undergo PCI. It is important to note that PCI is not without risks. PCI in the past has been shown to have a risk of morbidity of about 0.25% and risk of mortality of about 0.20%.
STUDY OBJECTIVE: Is stress-rest myocardial perfusion scintigraphy (MPS) beneficial in predicting who will show an increased exercise capacity after PCI? Can MPS testing help predict which patient groups will have the greatest decrease in symptoms after PCI?
PATIENTS: Patients were mostly male (86%) and most (63%) but not all (37%) had stable angina. Patients were recruited prospectively from the a group of patients that had a positive diagnostic angiogram and were already scheduled to undergo an elective PCI procedure.
METHODS: Within one month before having their PCI procedure, patients in the study underwent stress-rest myocardial perfusion scintigraphy using a same day, single-isotope protocol using Tc-99m tetrofosmin. Treadmill exercise was utilized for the stress test as much as possible. The patient's New York Heart Association functional status was assessed, and all patients answered the Seattle Angina Questionnaire. The cardiologists that performed the PCI procedures were blinded as to the outcome of the stress-rest perfusion scan. None of the PCI procedures were canceled due to the results of the perfusion scan.
At the 6 month follow-up visit after their PCI procedure, patients were once again evaluated for symptoms and functional status. A repeat treadmill test using the same protocol was performed in those patients that underwent treadmill stress ECG testing at baseline. Clinicians who performed this follow-up stress test were unaware of the results of the baseline test.
Scan results were analyzed quantitatively by the Cedars-Sinai AutoSPECT and AutoQuant software programs. A visually assessed semiquantitative analysis was also performed using summed scoring with a 17 segment 5-point scale. A consensus of two readers was utilized for statistical purposes.
RESULTS: There were 123 patients included in the study population. The treadmill exercise stress test was positive for evidence of inducible myocardial ischemia in 72%. The myocardial perfusion scan showed inducible hypoperfusion affecting greater than 10% of the myocardium in 20% of patients. The perfusion scan showed inducible hypoperfusion of 1% to 10% of the myocardium in 54% of the patients. The remaining 26% of patients had no reversible defects on perfusion scintigraphy.
At the 6 month follow-up visit, overall the average Seattle Angina Questionnaire score for all patients improved from 66 to 75 (P value less than 0.0001). The mean exercise capacity across all patients also improved, going from 7 up to 9 METS on average (P value less than 0.0001). However, the New York Heart Association functional class remained unchanged in 62%, it improved in 33%, and worsened in 5%.
The multivariate independent predictors of improvement were male gender, limiting chest pain on baseline treadmill stress testing, and the summed defect score.
CONCLUSION: Of all patients undergoing elective PCI in this study, only a small minority had a reversible myocardial perfusion defect affecting 10% or more of the myocardium. Independent predictors of improvement after revascularization were male sex, limiting chest pain on exercise stress testing, and inducible hypoperfusion on myocardial perfusion scintigraphy.
ARTICLE: Does myocardial perfusion scintigraphy predict improvement in symptoms and exercise capacity following successful elective percutaneous coronary intervention? Al-Housni MB, Hutchings F, Dalby M, Dubowitz M, Grocott-Mason R, Ilsley CD, Mason M, Mitchell AG, Kelion AD.J Nucl Cardiol. 2009 Jul 9. [Epub ahead of print]. From the Department of Cardiology, Royal Brompton and Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, United Kingdom. Pubmed.
BACKGROUND: The Courage Trial found a lack of survival benefit to percutaneous coronary intervention as compared to optimum medical therapy alone. However, in some patient subgroups, PCI was shown to have important quality of life benefits. Thus, there continues to remain doubt over who should undergo PCI. It is important to note that PCI is not without risks. PCI in the past has been shown to have a risk of morbidity of about 0.25% and risk of mortality of about 0.20%.
STUDY OBJECTIVE: Is stress-rest myocardial perfusion scintigraphy (MPS) beneficial in predicting who will show an increased exercise capacity after PCI? Can MPS testing help predict which patient groups will have the greatest decrease in symptoms after PCI?
PATIENTS: Patients were mostly male (86%) and most (63%) but not all (37%) had stable angina. Patients were recruited prospectively from the a group of patients that had a positive diagnostic angiogram and were already scheduled to undergo an elective PCI procedure.
METHODS: Within one month before having their PCI procedure, patients in the study underwent stress-rest myocardial perfusion scintigraphy using a same day, single-isotope protocol using Tc-99m tetrofosmin. Treadmill exercise was utilized for the stress test as much as possible. The patient's New York Heart Association functional status was assessed, and all patients answered the Seattle Angina Questionnaire. The cardiologists that performed the PCI procedures were blinded as to the outcome of the stress-rest perfusion scan. None of the PCI procedures were canceled due to the results of the perfusion scan.
At the 6 month follow-up visit after their PCI procedure, patients were once again evaluated for symptoms and functional status. A repeat treadmill test using the same protocol was performed in those patients that underwent treadmill stress ECG testing at baseline. Clinicians who performed this follow-up stress test were unaware of the results of the baseline test.
Scan results were analyzed quantitatively by the Cedars-Sinai AutoSPECT and AutoQuant software programs. A visually assessed semiquantitative analysis was also performed using summed scoring with a 17 segment 5-point scale. A consensus of two readers was utilized for statistical purposes.
RESULTS: There were 123 patients included in the study population. The treadmill exercise stress test was positive for evidence of inducible myocardial ischemia in 72%. The myocardial perfusion scan showed inducible hypoperfusion affecting greater than 10% of the myocardium in 20% of patients. The perfusion scan showed inducible hypoperfusion of 1% to 10% of the myocardium in 54% of the patients. The remaining 26% of patients had no reversible defects on perfusion scintigraphy.
At the 6 month follow-up visit, overall the average Seattle Angina Questionnaire score for all patients improved from 66 to 75 (P value less than 0.0001). The mean exercise capacity across all patients also improved, going from 7 up to 9 METS on average (P value less than 0.0001). However, the New York Heart Association functional class remained unchanged in 62%, it improved in 33%, and worsened in 5%.
The multivariate independent predictors of improvement were male gender, limiting chest pain on baseline treadmill stress testing, and the summed defect score.
CONCLUSION: Of all patients undergoing elective PCI in this study, only a small minority had a reversible myocardial perfusion defect affecting 10% or more of the myocardium. Independent predictors of improvement after revascularization were male sex, limiting chest pain on exercise stress testing, and inducible hypoperfusion on myocardial perfusion scintigraphy.
ARTICLE: Does myocardial perfusion scintigraphy predict improvement in symptoms and exercise capacity following successful elective percutaneous coronary intervention? Al-Housni MB, Hutchings F, Dalby M, Dubowitz M, Grocott-Mason R, Ilsley CD, Mason M, Mitchell AG, Kelion AD.J Nucl Cardiol. 2009 Jul 9. [Epub ahead of print]. From the Department of Cardiology, Royal Brompton and Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, United Kingdom. Pubmed.