MPI finds more CAD five years after treatment

Stress myocardial perfusion scintigraphy (MPS) when conducted five years following percutaneous coronary intervention (PCI) has the potential to pinpoint addition disease in more than half of patients, according to a study published ahead of print May 14 in JACC: Cardiovascular Interventions.

Researchers including Michael J. Zellweger, MD, from University Hospital in Basel, Switzerland, evaluated 339 patients who had received a stent five years earlier as a part of the Basel Stent Kosteneffektivitats Trial (BASKET) to gauge the number of adverse events including cardiac death, myocardial infarction or revascularization. The reason behind the study was to clear up uncertainty regarding appropriate use after two years following PCI in asymptomatic patients.

Results of the study showed that abnormal follow-up scans were correlated with progressive disease in remote blood vessels and other adverse events regardless of whether patients were symptomatic when imaged.

“These findings of the [BASKET] study document a strong prognostic value of routine stress imaging five years after successful PCI and stent implantation, irrespective of recurrent symptoms,” wrote Zellweger et al. “It is the first reasonably sized prospective study evaluating the prognostic value of routine stress MPS five years after PCI in patients selected neither for symptoms nor for particularly high risk. Importantly, the outcome of patients with normal MPS findings was excellent, but the prevalence of silent ischemia was high and its predictive power for future events similar to that of symptomatic ischemia.

A total of 205 of 339 patients had abnormal MPS results. There were seven cardiac deaths during a four-year period prior to follow-up, as well as 18 myocardial infarctions and 47 revascularizations. Patients with abnormal MPS had higher risk of adverse events. These results may bolster imaging two or more years after PCI but more study is required to validate increased use of MPS.

“Its predictive power lies more in the detection of persistent or progressive CAD in remote-vessel areas than in the diagnosis of very late intervention-related problems in the treated vessels,” concluded the authors. “Findings emphasize the importance of long-term secondary prevention of CAD and call for a randomized, controlled trial to define the optimal management of patients with ischemia very late after revascularization, irrespective of symptoms, and its cost-benefit implications.”