Catheterization and Cardiovascular Interventions 83:1055–1056 (2014)
Editorial Comment Saphenous Vein Grafts Intervention: Can Adenosine Make it Better? Harkawal Hundal, MD, and Joaquin E. Cigarroa,* MD, FACC, SCAI Knight Cardiovascular Institute, Oregon Health and Sciences University, Portland, Oregon
Patients with prior coronary artery bypass graft (CABG) surgery account for nearly one in five percutaneous coronary interventions (PCI) performed annually in the United States. About one-third of the interventions in CABG patients are performed on lesions within saphenous vein grafts (SVG). As a result, SVGs account for approximately 6% of all PCIs performed annually, according to the NCDR CathPCI registry [1]. Unfortunately, PCI of SVGs is an independent predictor of in-hospital mortality and is not only associated with a significant increase in adverse outcomes at 30 days but also rapid progression of disease in other segments of the vein graft. Except for drug eluting stents (DES) and distal protection devices (DPD), there have been no significant advances to improve outcomes of SVG interventions. In a metaanalysis, mortality in patients undergoing DES compared to bare metal stents (BMS) to SVG was reduced by 25%, target lesion revascularization by 43%, target vessel revascularization by 44%, and major cardiac outcomes by 39% [2]. DPDs such as the FilterWire EZ decrease the risk of no-reflow phenomenon and reduce the risk of periprocedural myocardial infarction. Despite the use of DES and DPDs, the rate of cardiac outcomes including myocardial infarction and death still occur in 10% of patients, an alarmingly high rate. The occurrence of no-reflow increases the risk of myocardial infarction and death substantially. Efforts including the use of more potent antiplatelet and antithrombotic therapies have not proved beneficial in reducing noreflow or periprocedural myocardial infarction. Currently, adenosine, verapamil, and/or nitroprusside are commonly used to treat no-reflow or slow-flow when they occur in an attempt to reverse the no-reflow phenomenon and improve clinical outcomes. In the VAPOR trial, pretreatment with intragraft verapamil prior to PCI resulted in reduction of no-reflow from 33.3 to 0% but C 2014 Wiley Periodicals, Inc. V
did not improve tissue perfusion and was limited by a small sample size of 22 patients [3]. In the current issue of the journal, Kapoor and colleagues present an intriguing use of adenosine to reduce no-reflow during SVG interventions. They build upon their data of adenosine in preconditioning prior to angioplasty in humans and the effects of intracoronary adenosine on reducing the risk of no-reflow in the animal model by assessing the effects of high dose adenosine versus placebo in SVGs. The hypothesis that high dose intragraft adenosine prior to SVG intervention would protect microvascular function was assessed by measuring surrogate markers including coronary flow reserve, thrombolysis in myocardial infarction (TIMI), thrombolysis in frame count, TIMI myocardial perfusion grade (TMPG). The adenosine group received an adenosine infusion of 2000 mg/10 min directly within the SVG compared to saline infusion of the same volume in the control group. Following infusion, the stents were deployed and measurements were repeated. Adenosine is known to impact platelet aggregation, vasoconstriction, and inhibit inflammatory processes, and may also promote myocardial ischemic preconditioning. In this well executed trial of 22 randomized patients, a consistent concordant benefit demonstrating improved flow and myocardial perfusion was observed in the group pretreated with adenosine. Specifically, there was a 36% reduction in no-reflow (defined as TIMI
Editorial Comment Saphenous Vein Grafts Intervention: Can Adenosine Make it Better? Harkawal Hundal, MD, and Joaquin E. Cigarroa,* MD, FACC, SCAI Knight Cardiovascular Institute, Oregon Health and Sciences University, Portland, Oregon
Patients with prior coronary artery bypass graft (CABG) surgery account for nearly one in five percutaneous coronary interventions (PCI) performed annually in the United States. About one-third of the interventions in CABG patients are performed on lesions within saphenous vein grafts (SVG). As a result, SVGs account for approximately 6% of all PCIs performed annually, according to the NCDR CathPCI registry [1]. Unfortunately, PCI of SVGs is an independent predictor of in-hospital mortality and is not only associated with a significant increase in adverse outcomes at 30 days but also rapid progression of disease in other segments of the vein graft. Except for drug eluting stents (DES) and distal protection devices (DPD), there have been no significant advances to improve outcomes of SVG interventions. In a metaanalysis, mortality in patients undergoing DES compared to bare metal stents (BMS) to SVG was reduced by 25%, target lesion revascularization by 43%, target vessel revascularization by 44%, and major cardiac outcomes by 39% [2]. DPDs such as the FilterWire EZ decrease the risk of no-reflow phenomenon and reduce the risk of periprocedural myocardial infarction. Despite the use of DES and DPDs, the rate of cardiac outcomes including myocardial infarction and death still occur in 10% of patients, an alarmingly high rate. The occurrence of no-reflow increases the risk of myocardial infarction and death substantially. Efforts including the use of more potent antiplatelet and antithrombotic therapies have not proved beneficial in reducing noreflow or periprocedural myocardial infarction. Currently, adenosine, verapamil, and/or nitroprusside are commonly used to treat no-reflow or slow-flow when they occur in an attempt to reverse the no-reflow phenomenon and improve clinical outcomes. In the VAPOR trial, pretreatment with intragraft verapamil prior to PCI resulted in reduction of no-reflow from 33.3 to 0% but C 2014 Wiley Periodicals, Inc. V
did not improve tissue perfusion and was limited by a small sample size of 22 patients [3]. In the current issue of the journal, Kapoor and colleagues present an intriguing use of adenosine to reduce no-reflow during SVG interventions. They build upon their data of adenosine in preconditioning prior to angioplasty in humans and the effects of intracoronary adenosine on reducing the risk of no-reflow in the animal model by assessing the effects of high dose adenosine versus placebo in SVGs. The hypothesis that high dose intragraft adenosine prior to SVG intervention would protect microvascular function was assessed by measuring surrogate markers including coronary flow reserve, thrombolysis in myocardial infarction (TIMI), thrombolysis in frame count, TIMI myocardial perfusion grade (TMPG). The adenosine group received an adenosine infusion of 2000 mg/10 min directly within the SVG compared to saline infusion of the same volume in the control group. Following infusion, the stents were deployed and measurements were repeated. Adenosine is known to impact platelet aggregation, vasoconstriction, and inhibit inflammatory processes, and may also promote myocardial ischemic preconditioning. In this well executed trial of 22 randomized patients, a consistent concordant benefit demonstrating improved flow and myocardial perfusion was observed in the group pretreated with adenosine. Specifically, there was a 36% reduction in no-reflow (defined as TIMI
