ADVERTISEMENT
The 2005 ACC/AHA/SCAI Percutaneous CoronaryIntervention Guidelines:Summarizing changes and some of the major recommendations
March 2006
It is important to keep in mind that these guideline documents are created in an attempt to define practices to meet the needs of most patients encountered in clinical practice. In creating these recommendations, a writing group reviews the available scientific evidence and expert opinion in order to form a consensus around specific statements. As a rule, Class I recommendations are made when there is clear evidence that the benefit greatly outweighs the risk and thus, the procedure/treatment should be performed. Class IIa recommendations reflect a condition where the evidence is not as strong, but the treatments/procedures are considered reasonable. Class IIb recommendations reflect a condition where equivocal data is available and the benefit-to-risk ratio is less certain. Class III recommendations are reserved for those treatments/procedures where the risks outweigh the benefits. These therapies should not be provided.
Recommendations for Operator Volume
The writing committee did not make major changes in the volume requirements for performance of PCI (Table 1). Originally a Class I guideline, operators who perform 75 or greater interventions per year operating in labs performing 400 or more interventions per year remains a Class I recommendation.
Operators performing 75 or more interventions per year in lower-volume cath labs performing 200 to 400 interventions per year are recommended as Class IIa. Operators performing less than 75 interventions per year in a low-volume cath lab continue to be discouraged, with a recommendation of Class III.
In the performance of primary PCI for ST-segment elevation myocardial infarction (STEMI), to satisfy the highest recommendation (Class I), operators who perform more than 75 interventions per year should have performed PCI on 11 or more patients having STEMI within labs performing more than 400 cases per year. The guideline committee clearly believes there is a strong correlation between not only operator volume and procedural success and complications, but also between institutional volume and clinical outcomes. Furthermore, patients with STEMI compose a unique subset to patients undergoing elective percutaneous interventions, requiring above-average PCI abilities and patient management skills. High-Risk Lesions and Left Main PCI Despite the introduction of drug-eluting stents, complex coronary lesions remain predictive of adverse events following PCI. These lesions have traditionally been classified as Type C, indicating a lower chance of procedural success with higher complication rates (than types A or B). Table 2 lists those factors that continue to predict higher-risk PCI. Clinical factors, such as advanced age, presence of unstable angina, diabetes, heart failure and multivessel disease, have all been shown to predict poorer outcomes from PCI than patients without such concomitant conditions.
Left main coronary artery disease is a specific lesion class and is commented on by the guidelines. In particular, they emphasize that bypass surgery remains the gold standard for patients with unprotected left main stenosis. However, citing recent publications, the guidelines also state that performance of PCI in patients with unprotected left main disease is reasonable if they were deemed not to be suitable candidates for bypass surgery. It is further recommended that these patients be carefully followed after PCI, with routine angiography in two to six months being a reasonable strategy. Surgical Backup The 2005 PCI guidelines made strong recommendations that the performance of PCI occur only at sites with surgical backup (Table 3). Specifically, as a Class I recommendation, all elective PCIs should be performed at centers with on-site surgical backup. A Class III recommendation was given to any elective percutaneous coronary intervention performed at institutions without surgical backup. The only statement to the contrary was a Class IIb recommendation for the performance of primary PCI in STEMI patients. This should only occur at institutions without on-site surgical backup if the procedure is performed by a physician with sufficient procedural annual volume and the institution has a plan in place for emergent transfer of patients to a nearby institution with surgical backup.
The 2005 guidelines do not support catheterization labs in rural areas where sufficient surgical volume does not exist to provide an on-site cardiac surgery program. This position is under continuous review, since there are many arguments to suggest that PCI should be performed in these types of hospitals given a sufficient volume and low complication rate.
The enhancement of PCI equipment and techniques has improved to the point that urgent transferal of patients to a cardiac surgeon has markedly diminished, regardless of the presence of on-site surgical backup. The committee did acknowledge these changes in practice, but at this point did not make recommendations for the performance of PCI at those sites without surgical backup. New Technology and Devices The committee strongly recommended that operators embrace the use of distal protection devices for all interventions on saphenous vein grafts (a Class I indication). This endorsement is strongly supported by the data that major adverse cardiac events (MACE) rates are reduced with the use of distal protection devices versus when these devices are not used. The guidelines do recommend that all interventionalists need to become facile with the use of at least one of the available devices.
The committee also made strong recommendations with respect to drug-eluting stents. These stents can be used as an alternative to bare-metal stents in those lesion subsets where randomized control trials have shown benefit from this technology. The committee clearly stated that their recommendation does encompass all types of lesions (e.g., left main coronary disease, STEMI, bifurcation lesions, and ostial coronary disease). Furthermore, they embrace the utilization of drug-eluting stents for the treatment of in-stent restenosis, giving it a Class IIa recommendation. Pharmacology The four years between the publication of PCI guidelines has seen dramatic change in the usage and availability of concomitant pharmacology for PCI. As a result, this section was extensively revised in the new literation (Table 4). The committee noted that aspirin should be administered prior to PCI in all patients (Class I). Furthermore, it is a Class I recommendation that 325 mg should be the dose of aspirin that all patients receive for the same duration that they receive clopidogrel (i.e., one month for bare-metal stent, three months for a sirolimus-eluting stent, and six months for a paclitaxel-eluting stent). The committee also made a Class I recommendation for the utilization of loading 300 mg clopidogrel in patients prior to performance of PCI, a position supported by satisfactory randomized studies. With respect to the utilization of glycoprotein (GP) IIb/IIIa inhibitors, the committee decided on a Class IIa recommendation, stating that these drugs are beneficial even if patients are already on aspirin and clopidogrel prior to PCI. In addition, there is a Class I recommendation for use of glycoprotein IIb/IIIa inhibitors in all patients presenting to the cardiac catheterization lab with unstable angina and non-ST elevation myocardial infarction. This applies whether GP IIb/IIIa inhibitors are used in an upstream fashion (before coming to the cath lab) or administered while the patient is on the table. This position is in sharp contrast to the committee’s recommendation on the use of bivalirudin. It received a Class IIa recommendation as an alternative therapy to the combination of unfractionated heparin and a glycoprotein IIb/IIIa inhibitor in low-risk PCI patients. The committee acknowledged the use of low-molecular weight heparin (enoxaparin) as an alternative to unfractionated heparin in patients presenting to lab with unstable angina and non-ST elevation MI, as well as recommending a higher loading dose of clopidogrel (600 mg).
In patients with stenting of an unprotected left main or other high-risk anatomy where the risk of stent thrombosis would be catastrophic, the committee made a Class IIb recommendation for the chronic dose of clopidogrel to be increased to 150 mg per day or the equivalent of producing 50% platelet inhibition. This appears to be in response to operators increasing the overall frequency of these types of interventions.
The recommendations on pharmacology are clearly data-driven, supporting the use of aspirin, clopidogrel, and glycoprotein IIb/IIIa inhibitors to decrease the acute complications of coronary stenting as well as the long-term thrombotic complications that exist in this patient population. The guidelines did not endorse the universal use of bivalirudin in all patient subsets, in contrast to many of the practice patterns currently employed in the United States. The anticoagulation regimens will continue to be reevaluated in each and every cath lab over the ensuing years.
In conclusion, in 2005, many of the new PCI guidelines represent unified wording to clarify conflicts arising from different guideline statements (i.e., unifying recommendations on treatment of ST-elevation MI, and/or non-ST elevation MI, and unstable angina). The major area of controversy that the committee had to deal with was regarding the performance of PCI without on-site surgery as well as the limited recommendation of bivalirudin relative to its clinical use in the U.S.
The ACC/AHA/SCAI has now instituted a continuous reevaluation of the generation of all guideline statements. The publication of new data will be incorporated to support changing practices when the data are sufficiently strong enough to do so. The ACC/AHA/SCAI has also set in motion a set of update companion statements which will assist in forming timely and appropriate procedures to support the best patient care.
Operators performing 75 or more interventions per year in lower-volume cath labs performing 200 to 400 interventions per year are recommended as Class IIa. Operators performing less than 75 interventions per year in a low-volume cath lab continue to be discouraged, with a recommendation of Class III.
In the performance of primary PCI for ST-segment elevation myocardial infarction (STEMI), to satisfy the highest recommendation (Class I), operators who perform more than 75 interventions per year should have performed PCI on 11 or more patients having STEMI within labs performing more than 400 cases per year. The guideline committee clearly believes there is a strong correlation between not only operator volume and procedural success and complications, but also between institutional volume and clinical outcomes. Furthermore, patients with STEMI compose a unique subset to patients undergoing elective percutaneous interventions, requiring above-average PCI abilities and patient management skills. High-Risk Lesions and Left Main PCI Despite the introduction of drug-eluting stents, complex coronary lesions remain predictive of adverse events following PCI. These lesions have traditionally been classified as Type C, indicating a lower chance of procedural success with higher complication rates (than types A or B). Table 2 lists those factors that continue to predict higher-risk PCI. Clinical factors, such as advanced age, presence of unstable angina, diabetes, heart failure and multivessel disease, have all been shown to predict poorer outcomes from PCI than patients without such concomitant conditions.
Left main coronary artery disease is a specific lesion class and is commented on by the guidelines. In particular, they emphasize that bypass surgery remains the gold standard for patients with unprotected left main stenosis. However, citing recent publications, the guidelines also state that performance of PCI in patients with unprotected left main disease is reasonable if they were deemed not to be suitable candidates for bypass surgery. It is further recommended that these patients be carefully followed after PCI, with routine angiography in two to six months being a reasonable strategy. Surgical Backup The 2005 PCI guidelines made strong recommendations that the performance of PCI occur only at sites with surgical backup (Table 3). Specifically, as a Class I recommendation, all elective PCIs should be performed at centers with on-site surgical backup. A Class III recommendation was given to any elective percutaneous coronary intervention performed at institutions without surgical backup. The only statement to the contrary was a Class IIb recommendation for the performance of primary PCI in STEMI patients. This should only occur at institutions without on-site surgical backup if the procedure is performed by a physician with sufficient procedural annual volume and the institution has a plan in place for emergent transfer of patients to a nearby institution with surgical backup.
The 2005 guidelines do not support catheterization labs in rural areas where sufficient surgical volume does not exist to provide an on-site cardiac surgery program. This position is under continuous review, since there are many arguments to suggest that PCI should be performed in these types of hospitals given a sufficient volume and low complication rate.
The enhancement of PCI equipment and techniques has improved to the point that urgent transferal of patients to a cardiac surgeon has markedly diminished, regardless of the presence of on-site surgical backup. The committee did acknowledge these changes in practice, but at this point did not make recommendations for the performance of PCI at those sites without surgical backup. New Technology and Devices The committee strongly recommended that operators embrace the use of distal protection devices for all interventions on saphenous vein grafts (a Class I indication). This endorsement is strongly supported by the data that major adverse cardiac events (MACE) rates are reduced with the use of distal protection devices versus when these devices are not used. The guidelines do recommend that all interventionalists need to become facile with the use of at least one of the available devices.
The committee also made strong recommendations with respect to drug-eluting stents. These stents can be used as an alternative to bare-metal stents in those lesion subsets where randomized control trials have shown benefit from this technology. The committee clearly stated that their recommendation does encompass all types of lesions (e.g., left main coronary disease, STEMI, bifurcation lesions, and ostial coronary disease). Furthermore, they embrace the utilization of drug-eluting stents for the treatment of in-stent restenosis, giving it a Class IIa recommendation. Pharmacology The four years between the publication of PCI guidelines has seen dramatic change in the usage and availability of concomitant pharmacology for PCI. As a result, this section was extensively revised in the new literation (Table 4). The committee noted that aspirin should be administered prior to PCI in all patients (Class I). Furthermore, it is a Class I recommendation that 325 mg should be the dose of aspirin that all patients receive for the same duration that they receive clopidogrel (i.e., one month for bare-metal stent, three months for a sirolimus-eluting stent, and six months for a paclitaxel-eluting stent). The committee also made a Class I recommendation for the utilization of loading 300 mg clopidogrel in patients prior to performance of PCI, a position supported by satisfactory randomized studies. With respect to the utilization of glycoprotein (GP) IIb/IIIa inhibitors, the committee decided on a Class IIa recommendation, stating that these drugs are beneficial even if patients are already on aspirin and clopidogrel prior to PCI. In addition, there is a Class I recommendation for use of glycoprotein IIb/IIIa inhibitors in all patients presenting to the cardiac catheterization lab with unstable angina and non-ST elevation myocardial infarction. This applies whether GP IIb/IIIa inhibitors are used in an upstream fashion (before coming to the cath lab) or administered while the patient is on the table. This position is in sharp contrast to the committee’s recommendation on the use of bivalirudin. It received a Class IIa recommendation as an alternative therapy to the combination of unfractionated heparin and a glycoprotein IIb/IIIa inhibitor in low-risk PCI patients. The committee acknowledged the use of low-molecular weight heparin (enoxaparin) as an alternative to unfractionated heparin in patients presenting to lab with unstable angina and non-ST elevation MI, as well as recommending a higher loading dose of clopidogrel (600 mg).
In patients with stenting of an unprotected left main or other high-risk anatomy where the risk of stent thrombosis would be catastrophic, the committee made a Class IIb recommendation for the chronic dose of clopidogrel to be increased to 150 mg per day or the equivalent of producing 50% platelet inhibition. This appears to be in response to operators increasing the overall frequency of these types of interventions.
The recommendations on pharmacology are clearly data-driven, supporting the use of aspirin, clopidogrel, and glycoprotein IIb/IIIa inhibitors to decrease the acute complications of coronary stenting as well as the long-term thrombotic complications that exist in this patient population. The guidelines did not endorse the universal use of bivalirudin in all patient subsets, in contrast to many of the practice patterns currently employed in the United States. The anticoagulation regimens will continue to be reevaluated in each and every cath lab over the ensuing years.
In conclusion, in 2005, many of the new PCI guidelines represent unified wording to clarify conflicts arising from different guideline statements (i.e., unifying recommendations on treatment of ST-elevation MI, and/or non-ST elevation MI, and unstable angina). The major area of controversy that the committee had to deal with was regarding the performance of PCI without on-site surgery as well as the limited recommendation of bivalirudin relative to its clinical use in the U.S.
The ACC/AHA/SCAI has now instituted a continuous reevaluation of the generation of all guideline statements. The publication of new data will be incorporated to support changing practices when the data are sufficiently strong enough to do so. The ACC/AHA/SCAI has also set in motion a set of update companion statements which will assist in forming timely and appropriate procedures to support the best patient care.
NULL
