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(Circulation. 2005;112:3509-3534.)
© 2005 American Heart Association, Inc.
Controversies in Cardiovascular Medicine |
| Introduction |
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| The Need to Improve Access to Primary PCI for Patients With AMI |
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The most important determinant of how the patient with STEMI is treated is whether or not primary PCI is readily available. Most patients with AMI present to community hospitals,11 where primary PCI is generally not available and is even prohibited in many states. The delivery of this preferred reperfusion strategy for STEMI must be increased several-fold at the hospitals where most patients present. The great advances in the science and technology of primary PCI that have been made at academic centers must be accompanied by their effective dissemination into the community; otherwise, the benefit of much of this crucial work is lost. Every acute-care hospital in the United States can and should take all necessary steps to ensure that patients with STEMI can be treated with timely PCI. All tertiary centers with PCI programs should offer primary PCI 24 hours per day, 7 days per week for STEMI patients who initially present there and should stand ready to accept STEMI patients in transfer from other acute-care hospitals at all hours.
Approaches to Improve Access to Primary PCI
Early Rapid Transfer and Prehospital Ambulance Triage to PCI Centers: Advantages and Disadvantages
The lack of an on-site PCI program need not prevent a hospital from offering treatment with primary PCI. The advantage of primary PCI over fibrinolytic therapy in reducing death, reinfarction, and stroke persists even when patients must be transferred for primary PCI.1,12 Two notable European trials, The Second Danish Trial of Acute Myocardial Infarction (DANAMI-2)13 and The Second Primary Angioplasty in Patients Transferred from General Community Hospitals to Specialized PTCA Units Trial (PRAGUE-2),14 have convincingly demonstrated that early and rapid transfer for primary PCI yields superior outcomes compared with local fibrinolytic therapy in most patients with STEMI who present to noninterventional centers. These strategies of early rapid transfer and prehospital ambulance triage of such patients, analogous to the trauma center model, are beginning to be examined and implemented in various regions in the United States, including Boston, Mass, Durham, NC, and Minneapolis, Minn.1517 The applicability of these strategies is limited mostly to urban areas, where the transport time to a PCI center may be relatively short. The strategy of prehospital ambulance triage is further limited by the fact that only half of all patients with AMI are transported to the emergency department by ambulance.18
Universal triage or transfer of patients with STEMI to cardiac surgery centers is not possible in many areas of this country where acute-care hospitals are geographically remote from tertiary centers. Helicopters cannot always fly owing to weather conditions, and ground transport may be slowed by traffic conditions in congested areas or by the need to transport over long distances. The liability risk regarding interhospital transfer of patients in the throes of AMI is appreciable. Unfortunately, some acute-care hospitals might feel pressure to not transfer all patients with STEMI because of institutional pride and loss of reimbursement. In addition, moving all patients with STEMI to tertiary centers could quickly flood the capability of many of these centers. (It is notable that in the PRAGUE-2 study, 2 of the 7 primary PCI centers in Prague did not have on-site cardiac surgery capability.) Many tertiary centers still do not offer primary PCI as routine first-line care, even for their own patients with STEMI, and thus may not have effective protocols to perform immediate PCI on critically ill patients whom they accept in transfer or by prehospital ambulance triage. With the aging of the "baby boomer" population, the current "epidemic" of diabetes and obesity, and the increasing recognition of the need to provide timely primary PCI in a large majority of patients with STEMI, this patient load will increase even further.
Even when rapid transfer is possible, not all patients are stable enough to transfer. These highest-risk patients are the very ones who are most likely to benefit from primary PCI. The transfer process itself involves risk and delay and can even be a barrier to revascularization, as discussed below. Thus, the applicability and benefits of transfer hinge on whether it can be accomplished rapidly and whether the patient can be stabilized for safe transfer.
The mortality benefit of primary PCI decreases as the time delay to PCI increases, and this benefit may disappear when the delay to PCI is more than 1 hour compared with the time to administration of a fibrinolytic agent.19 Patients in the United States who are transferred for primary PCI are treated 71 minutes later than patients who receive primary PCI locally (171 versus 100 minutes), according to data from the NRMI (Figure 2).20 This same NRMI registry demonstrates that a door-to-balloon time of 2.5 to 3 hours, as seen in patients transferred for PCI, is associated with a 60% increase in risk-adjusted mortality compared with <2 hours from door to balloon time.21
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Thus, the data from DANAMI-2 and PRAGUE-2, which demonstrate that transfer for PCI yields superior outcomes compared with local fibrinolytic therapy, may not be directly applicable in the United States22; the mean times to PCI in transferred patients were &1 hour faster in these European studies than in the US NRMI registries.20 Only 4% of patients transferred for primary PCI in the NRMI registries received PCI within 90 minutes of first presentation, and only 15% received it within 2 hours.23 In contrast, 6 studies of primary PCI at US hospitals without on-site cardiac surgery reported door-to-balloon times of 80 to 110 minutes in an aggregate of 4395 patients (Table 1).
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Moreover, even when the transfer system was as streamlined and as efficient as it was in these countries, transfer for primary PCI was not possible in 4% of patients in the DANAMI-2 study and 1% of patients in the PRAGUE-2 study who were too unstable to transfer. Three of the 4 patients in PRAGUE-2 who could not be transferred died. (Similar information on such patients in DANAMI-2 was not reported.) Of those who were transferred, 2 patients died during transfer in PRAGUE-2, and 3 others had ventricular fibrillation en route. In DANAMI-2, 8 patients had ventricular fibrillation during transfer (1.4%); 1 of these could not be resuscitated and died an hour after arrival.
In these studies, many of the sickest patients, who might have benefited the most from immediate PCI, were unable to be transferred for intervention. Primary PCI at the point of first hospital contact could be lifesaving in patients too unstable for transfer to a tertiary center. In the United States, where the transfer system is not as streamlined as it was in the DANAMI-2 and PRAGUE-2 studies, locally available PCI can obviate the much greater delay, and sometimes the barrier, of the transfer process.
PCI at the point of first hospital contact is especially important for patients with cardiogenic shock. Patients in cardiogenic shock are very difficult to stabilize sufficiently for transfer and more difficult to transfer rapidly. In some cases, transfer may not be possible in these critically ill patients. Yet these are the very patients in whom rapid and effective PCI is potentially the most lifesaving. Early revascularization of ischemic myocardium while it is still viable, with intra-aortic balloon pump support, offers the best possibility of rapidly improving cardiac function and restoring adequate circulation to the body. In the Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock (SHOCK) study, randomization to mechanical revascularization within the first 6 hours of infarction conferred the greatest survival advantage of all subgroups examined for patients with cardiogenic shock.24
Unnecessary centralization of care to tertiary centers can lead to inappropriate underutilization of indicated cardiac procedures in the community, particularly in women, ethnic minorities, and the uninsured.2528 A study involving individuals hospitalized for AMI in 231 hospitals in New York State found that patients in the highest quintile of income were 74% more likely to receive PCI than those in the lowest quintile of income.29
Development of More PCI Centers at Qualified Hospitals Without Cardiac Surgery
There is currently a great need for more centers that are capable of performing emergency PCI. Many acute-care community hospitals are geographically remote from tertiary centers. The transfer of ever-increasing numbers of patients with STEMI to tertiary centers that provide primary PCI will place an increasing burden on their capacity. The need for more PCI centers will increase far more rapidly than the need for more cardiac surgery facilities. With the increasing patient load, the uncoupling of PCI programs from the requirement for on-site cardiac surgery can improve access to timely PCI while avoiding the pressure to build new low-volume cardiac surgery facilities to support PCI.
Only 39% of hospitals in the NRMI provide cardiac surgery.30 Most patients with AMI present to community hospitals without cardiac surgery,11 yet 600 of these hospitals have diagnostic cardiac catheterization laboratories.31 These diagnostic laboratories are often staffed by experienced interventionalists who also perform PCI at surgical centers. Thus, many community hospital catheterization laboratories may have the potential to establish effective primary PCI programs if they can provide experienced personnel, optimal interventional and imaging equipment, and formal arrangements for expeditious transfer to a surgical center.
Outcomes of Primary PCI Programs With Off-Site Surgery Backup: Evidence From the Literature
Fifteen registries and studies have demonstrated that community hospitals without on-site cardiac surgery backup can establish safe and effective primary PCI programs with excellent outcomes that are not compromised by the lack of on-site cardiac surgery (Table 1).3249 Weaver and coworkers34,35 compared the outcomes of 472 patients with AMI treated with primary PCI in hospitals without on-site cardiac surgery with those of 592 patients with AMI in hospitals with surgery backup, using data from the Myocardial Infarction Triage and Intervention (MITI) Registry. The median times to treatment, procedural success rates, and in-hospital and 1-year mortality rates were not different for the 2 types of hospitals.
Our group has reported the outcomes of immediate coronary angiography with primary PCI when appropriate in 506 patients with AMI at 2 community hospitals without cardiac surgery.39 This is the largest single-group experience of primary PCI in hospitals without on-site cardiac surgery reported to date. In this series, more than two thirds of the patients had clinical high-risk predictors (Killip class 3 or 4, age
75 years, anterior AMI, out-of-hospital ventricular fibrillation) and/or angiographic high-risk predictors (left main or 3-vessel disease or ejection fraction <45%). Sixty-one percent were ineligible for fibrinolytic therapy. The median time from emergency department presentation to first balloon inflation was 109 minutes. The overall in-hospital mortality rate was 5.3%. In 56 patients who presented with cardiogenic shock, the mortality rate was 23%, and in patients without shock, it was 3.0%. Stroke occurred in 2 patients, and no patient had intracerebral bleeding. Outcomes for patients who presented at night or on weekends were similar to those who presented during working hours, despite a somewhat longer door-to-balloon time due to the call-back status of the catheterization laboratory team. No patient died or needed emergency aortocoronary bypass surgery because of new myocardial jeopardy caused by a complication of the cardiac catheterization or interventional procedure. The low mortality rate in patients having primary PCI was sustained at 6 months after discharge. Our rates of successful intervention, reinfarction, stroke, and death in this series compared favorably with the outcomes of large, high-volume surgical centers reported in the literature.
Aversano and coworkers42 accomplished the only randomized study of primary PCI versus fibrinolysis at hospitals with off-site surgery backup. The Cardiovascular Patient Outcomes Research Team (C-PORT) trial, with 453 patients enrolled, demonstrated the superiority of primary PCI in reducing the composite end point of death, recurrent AMI, and stroke at 6 weeks and 6 months compared with fibrinolytic therapy. The median length of stay was also reduced in the primary PCI group. No patient was transferred to a surgical center because of a complication of the PCI procedure. (Unfortunately, this trial had to be stopped before the planned enrollment was completed because funding could not be secured.)
Kutcher and colleagues,45 in a preliminary report from the American College of Cardiology National Cardiovascular Data Registry (ACC-NCDR), found that the rates of PCI success, emergency surgery, and death for both primary and nonemergent PCI procedures at hospitals without on-site cardiac surgery were extremely favorable and similar to those at cardiac surgery centers. Sanborn and colleagues46 analyzed data from the NRMI that compared the outcomes of primary PCI at surgical hospitals with those of 1874 patients at 97 hospitals without on-site cardiac surgery. This is the largest aggregate experience of primary PCI at nonsurgical hospitals reported to date. There were comparable in-hospital mortality rates and quality-of-care indicators between the types of hospitals, whereas hospitals with off-site surgery backup had shorter door-to-balloon times than those with cardiac surgery. The outcomes of 4.7% of the patients who were transferred to another institution from hospitals without cardiac surgery were unknown, which precludes a comparison of in-hospital mortality rates.
Singh and colleagues47 compared the outcomes of 160 patients with STEMI and non-STEMI who underwent primary PCI at a Mayo Clinic satellite hospital 85 miles away from the tertiary surgical center with 160 matched controls treated with primary PCI at the surgical center. The rates of procedural success, in-hospital and 6-month mortality, Q-wave myocardial infarction, and target-vessel revascularization were low and were similar in the 2 groups. No patient was referred for emergency CABG surgery for failed PCI.
Wharton and coworkers48 prospectively enrolled 500 patients with high-risk STEMI at 19 community hospitals with off-site cardiac surgery backup in the Primary Angioplasty in Acute Myocardial InfarctionNo Surgery On Site (PAMI-No SOS) study. To be enrolled, patients had to have at least 1 of the following high-risk qualifiers: Age >70 years (no upper age limit), anterior myocardial infarction or left bundle-branch block, heart rate >100 bpm, systolic blood pressure >100 mm Hg, or Killip class 2 or 3 congestive heart failure. Lower-risk patients and those with shock were excluded from enrollment to duplicate the selection criteria for the randomized Air PAMI study.50 The 30-day mortality rate in this very-high-risk group was extremely favorable at 3.4%. Outcomes were similar to those for patients transferred for primary PCI in Air PAMI, and reperfusion was more rapid by a mean of 67 minutes.
Wennberg and colleagues49 analyzed Medicare data from 1999 to 2001 and found that 178 hospitals performed PCI without on-site cardiac surgery. The rates of in-hospital mortality and bypass surgery in patients receiving primary and rescue PCI at these hospitals were similar to those at hospitals with on-site surgery. (Hospitals without on-site cardiac surgery that performed <50 Medicare PCI procedures per year had higher mortality, but only in their nonprimary/rescue PCI patients. This particular group performed an institutional average of only 6.3 Medicare nonprimary/rescue PCI procedures per year, or 18.9 per year if every hospital performed PCI in only 1 of the 3 years studied.)
These and 7 other reports from hospitals without on-site cardiac surgery indicate that primary PCI can be provided safely and effectively in a high-risk patient population, with outcomes similar to those reported from high-volume surgery centers. We are aware of no clinical evidence that suggests that primary PCI offered in hospitals without open heart surgery is less safe or results in poorer outcomes than primary PCI at tertiary surgery centers. To the contrary, this increasing body of evidence confirms that this potentially lifesaving procedure is delivered as well and more quickly at qualified hospitals with off-site cardiac surgery backup as at tertiary centers.50a This evidence indicates that the risk to those who need primary PCI and do not receive it is likely to be far greater than any postulated risk associated with the lack of an on-site surgery program.
Institutional Resources and Program Development Requirements for Primary PCI Programs at Hospitals Without Cardiac Surgery
To establish optimal primary PCI programs at hospitals without cardiac surgery, rigorous standards must be met. We have proposed operator and institutional requirements for primary PCI at hospitals with off-site cardiac surgery backup, as shown in Table 2.39,51,52 These standards have been affirmed in the most recent revisions of the American College of Cardiology/American Heart Association (ACC/AHA) PCI and AMI guidelines.53,54 Meeting these requirements presents a sometimes daunting challenge. Community hospitals offering primary PCI with off-site surgery backup must have experienced high-volume interventionalists on staff who routinely perform nonemergent PCI, a catheterization laboratory staff that has gained experience at a busy interventional laboratory, a complete array of interventional equipment (including thrombectomy and distal protection devices and covered stents), well-defined clinical and angiographic selection criteria for the performance of primary PCI and for emergency transfer to a tertiary surgery center (Table 3), and established protocols and agreements to accomplish emergency transfers expeditiously (Table 4).
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Primary PCI should be offered as routine, first-line therapy for patients presenting with STEMI 24 hours per day, 7 days per week. A critical pathway for primary PCI from prehospital contact through hospital discharge, such as the one shown in Figure 3, should be implemented on a hospital-wide basis. A rigorous program to monitor outcomes and foster quality improvement is imperative and requires a dedicated institutional data and quality coordinator. We strongly urge that any hospital that provides PCI with off-site cardiac surgery backup enroll in the ACC-NCDR.
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A higher institutional volume of primary PCI correlates with improved mortality rates. In the NRMI-2 registry, the odds-adjusted mortality of patients with STEMI who received primary PCI was 33% lower at institutions that performed more than 33 primary PCI procedures per year than at institutions that performed fewer than 12 per year.55 These higher-volume hospitals also had faster times to reperfusion. On the basis of these data, the current ACC/AHA PCI and AMI guidelines recommend a minimum volume of 36 primary PCI procedures per year for nonsurgical hospitals that perform primary PCI. This minimum volume recommendation of the ACC/AHA guidelines helps to ensure a strong institutional commitment to providing primary PCI as routine, first-line therapy on a 24-hour-per-day, 7-day-per-week basis. A single and well-practiced care plan for treatment of STEMI patients presenting at all hours can maximize institutional and operator volumes, streamline care paths, and minimize door-to-balloon times and thus optimize outcomes.
Have the ACC/AHA Guidelines for STEMI Kept Pace With the Evidence?
The latest revision of the ACC/AHA guidelines for STEMI, published in July 2004,54 has not changed the Class IIb indication status for primary PCI at hospitals without on-site cardiac surgery ("usefulness/efficacy less well established by evidence/opinion"). We believe that the increasing body of newer literature now provides sufficient evidence to move this classification upward to Class IIa ("weight of evidence/opinion is in favor of usefulness/efficacy"). Despite the decision of the majority of the members of the STEMI guidelines committee to maintain the Class IIb indication, several other cardiology thought-leaders have recently encouraged primary PCI at qualified hospitals with off-site surgery backup or directly advocated this classification upgrade.
For example, Weaver56 observes that most patients with AMI are admitted to hospitals without cardiac surgery and thus calls for more qualified nonsurgical hospitals to establish primary PCI programs. Noting that some states require on-site cardiac surgery for hospitals that perform PCI, he states, "In my mind, these restrictive regulations must be changed." He continues, "Geography should not determine the type of treatment we receive for life-threatening conditions such as AMI." Ryan57 states, "... for rural America, it is important to nurture and further develop existing institutions without nearby surgical capability that can demonstrate their ability to undertake life-saving techniques, such as primary PCI, safely and effectively to make that technology more available to the patient in need." Cannon58 concludes, "... if a community hospital makes a strong institutional commitment to establishing a comprehensive program, performance of primary PCI will be beneficial to patients." Brodie59 urges that the indication for primary PCI at hospitals with off-site backup be changed to Class IIa: "We, as a cardiology community, should vigorously promote making mechanical reperfusion more available. The performance of primary PCI at facilities with interventional capabilities but without on-site cardiac surgery will help us toward this goal."
We also advocate advancing the classification of primary PCI at hospitals with off-site surgery backup to Class IIa. The fact that 80% of patients with STEMI in the United States are not treated with primary PCI is a major public health problem. We strongly encourage the increased availability of primary PCI in broader geographical regions. Upgrading the indication to Class IIa would be a very important step toward facilitating the delivery of primary PCI to a greater proportion of patients with STEMI. In the words of Weaver, "Too often in cardiology, we generate evidence to support a new treatment [primary PCI] but fail to effectively implement it. This cannot be another such example!"56
Table 1 summarizes basic elements of the 15 published registries and studies of primary PCI at hospitals without on-site cardiac surgery. The first 6 studies were published before the 2001 ACC/AHA PCI guidelines53 and included 1076 PCI procedures at 10 hospitals. The Class IIb indication designated in the 2001 PCI guidelines was based on 5 of the first 6 studies (the 50-patient Moquet report37 was not referenced in these guidelines), which reported a total of 1026 PCI procedures at 9 sites. In these 6 studies, the procedural success rate averaged 90%, with an in-hospital mortality rate of 7.6%. Only 10 (0.93%) of 1076 patients required emergency coronary bypass surgery for PCI failure.
Since publication of the 2001 ACC/AHA PCI guidelines, 9 more studies have been recognized, including 1 randomized trial and 2 abstracts. These newer studies include 7319 more patients from 180 sites and bring the total number of reported patients having primary PCI at nonsurgical hospitals to 8359. In these more recent studies, performed in the era of newer-generation stents and antiplatelet medications, the procedural success rate improved to 95% in the 6 studies that reported these data, with an in-hospital mortality rate of only 5.8% for all studies. (Five of these studies included patients with cardiogenic shock.) Only 11 (0.53%) of the 2055 patients in whom the information is available required emergency coronary bypass surgery for PCI failure.
Very importantly, door-to-balloon times were reported in 9 of these 15 studies in an aggregate of 5750 patients. The reperfusion times in these studies ranged from 80 to 110 minutes, or 61 to 91 minutes faster than in patients transferred for PCI according to the most recent NRMI data (Figure 2).20
Of these 9 newer studies, it is noteworthy that the study by Politi et al44 was not cited in the STEMI guidelines, and the study by Wennberg et al49 was published after the guidelines were released. These 2 studies, which report an aggregate of 2796 primary PCI procedures performed without on-site surgery, were thus not considered by the STEMI guidelines committee. In addition, the studies by Sanborn et al,46 Singh et al,47 and Wharton et al48 were published only 1 month before the STEMI guidelines were released. Thus, the STEMI guidelines committee may not have been able to fully consider the implications of these 3 other studies, which report an aggregate of 2474 more primary PCI procedures. We wonder whether the STEMI guidelines committee would have reached the same conclusion about the Class IIb indication for primary PCI at hospitals with off-site surgery backup had these 5 studies, with an aggregate of 5270 procedures, been available earlier in the guidelines writing process. In view of these 9 new reports, which include 1 new randomized trial, of very favorable outcomes in nearly 7 times as many primary PCI procedures from 18 times as many hospitals as were included in the studies cited by the 2001 ACC/AHA PCI guidelines, and with no unfavorable evidence published to the contrary, we assert that there is now quite sufficient evidence (at a guidelines-defined "Level of Evidence B," or "data derived from a single randomized trial, or nonrandomized studies") to support a guidelines upgrade to a Class IIa indication ("weight of evidence ... in favor of usefulness/efficacy") for primary PCI at qualified nonsurgical hospitals.
Well over 100 community hospitals in the United States are now providing primary PCI with off-site backup as routine treatment for patients with STEMI. Because this represents a costly and potentially controversial endeavor, it is difficult to ascribe selfish or financial motives to this effort, as some have done. These community hospitals have stepped out ahead of the guidelines and chosen to make this extraordinary and costly commitment because they want to provide this "best" therapy to a greater proportion of their patients with STEMI. It is regrettable that this strong and growing grass-roots movement in the United States has no strong support from the ACC/AHA guidelines themselves and no voice of experience in community intervention sitting on the guidelines committees.
It is unlikely that there will be any more randomized trials of this approach. The 1 randomized trial, C-PORT,41 was stopped before completion of the planned enrollment because funding could not be secured. In lieu of a randomized trial, all hospitals that perform PCI with off-site cardiac surgery backup should be required to submit their data to the ACC-NCDR. As the amount of information on this approach mounts, the likelihood of future guidelines indication classification upgrades should also increase, not only for primary PCI but also for the growing movement to provide selective nonemergent PCI at hospitals with off-site surgery backup. (In the report from NRMI,46 50 hospitals provided elective as well as primary PCI with off-site cardiac surgery backup.)
In 1988, the first ACC/AHA guidelines on percutaneous transluminal coronary angioplasty took a very strong and uncompromising position on this issue. These guidelines stated, "An experienced cardiovascular surgical team should be available within the institution for all angioplasty procedures," and "there should be no exception to this requirement." They further stated, "all arrangements requiring transportation of patients to off-site surgical facilities fail to meet the necessary standards of care exercised by prudent physicians and cannot be condoned"60 [emphasis added]. Despite this uncompromising position, interventionalists at many community hospitals without on-site cardiac surgery in the United States (including ourselves) nevertheless began to offer primary PCI to high-risk and lytic-ineligible patients who had no reperfusion alternative, once the advantages of primary PCI had been described by its earliest investigators.61,62 The ACC/AHA guidelines for AMI and PCI, cognizant of this early experience at hospitals with off-site surgery backup (Table 1),32,3436,38,39 have evolved considerably over the 16 years since the 1988 guidelines were published. We hope for and look forward to the further evolution of these guidelines.
| Conclusions |
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There are 3 necessary and interdependent solutions to improving the delivery of primary PCI to patients with STEMI: (1) The development of rapid and effective emergency transfer protocols to qualified PCI centers; (2) the development of regional systems for prehospital ambulance triage of STEMI patients to PCI centers with 24-hour, 365-day emergency capability (after the model of trauma centers); and (3) the development of more PCI centers at qualified hospitals with off-site cardiac surgery backup. These 3 solutions are interdependent; the widespread use of prehospital ambulance triage and emergency transfer will ultimately depend on the development of more interventional programs in broader geographic regions. The first 2 solutions alone are not adequate by themselves, for the reasons of access, demand, and rapid delivery that have been discussed.
The evidence from the literature and the vast experience at numerous community hospitals in the United States demonstrate that safe, effective, and rapid primary PCI can be delivered at qualified hospitals with off-site cardiac surgery backup that meet rigorous standards. The lack of cardiac surgery backup per se need not limit the safety or efficacy of this valuable therapy for AMI. Improving the delivery of coronary intervention to increasing numbers of patients with STEMI in more centers over broader geographic regions will provide a substantial healthcare benefit to society. The processes to accomplish this should be supported and encouraged by the responsible regulatory agencies and the appropriate scientific bodies of the medical profession.
| Acknowledgments |
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| References |
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One of the most contentious debates in cardiology in the last decade has been that of choice of reperfusion therapy in patients with ST-segment elevation myocardial infarction (STEMI); specifically, whether thrombolytic therapy or primary percutaneous coronary intervention (PCI) is more effective in these patients. Although data from 23 randomized controlled trials show that primary PCI is superior to thrombolytic therapy by significantly decreasing short-term death, nonfatal reinfarction, stroke, and the combined end point of death, nonfatal reinfarction, and stroke,1 the majority of STEMI patients still receive thrombolytic therapy owing to the limited availability of primary PCI.2 The next debate in this area is likely to be whether STEMI patients should be transferred to a tertiary, high-volume primary PCI center for primary PCI or undergo this procedure in community hospitals. Although these 2 strategies are not mutually exclusive, we present data supporting the case that emergent transfer for primary PCI to high-volume PCI centers results in better clinical outcomes and therefore is the strategy of choice.
| Limited Availability of Primary PCI |
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Role of Community Hospitals With PCI Capability but Not Cardiac Surgery Capability
Emergent coronary artery bypass (CABG) surgery due to acute or threatened closure of the coronary artery during a PCI procedure has become extremely infrequent with the increased use of intracoronary stents. For example, only 4 (0.4%) of the 1100 STEMI patients enrolled in the Primary Angioplasty in Myocardial Infarction (PAMI)-2 trial required emergent CABG for a failed PCI procedure9; in a review of 6 major randomized trials comparing balloon angioplasty to coronary stenting in STEMI,1015 only 6 (0.31%) of 1953 patients required emergent CABG for a failed PCI.16 It is against this background that early observational studies on the safety and efficacy of primary PCI in STEMI patients admitted to hospitals without on-site cardiac surgery were performed.
The largest prospective multicenter registry to date that evaluated this strategy compared the clinical outcomes of 500 high-risk STEMI patients undergoing primary PCI in community hospitals without on-site cardiac surgery (the Primary Angioplasty in acute Myocardial Infarction at hospitals with No Surgery On-Site [PAMI-No SOS])17 with 71 high-risk STEMI patients transferred for primary PCI (the transfer arm of the Air PAMI trial).18 In this nonrandomized study, significantly more patients presenting with anterior infarctions were transferred for primary PCI rather than undergoing primary PCI in the community hospital (77% versus 52%, P<0.0001). This is likely secondary to selection bias and is a major limitation of the study. Transferred patients had a mean delay to treatment of 67 minutes (187 versus 120 minutes, P<0.0001) and lower rates of final Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow (86% versus 96%, P=0.004) compared with patients treated on site. Two patients who underwent primary PCI in community hospitals without on-site cardiac surgery required emergent transfer for surgery due to a failed PCI (0.4%), and another 5% were transferred owing to critical coronary anatomy amenable to elective surgical revascularization. In the transfer arm of the Air PAMI trial, 5.6% of the patients underwent surgery for critical coronary anatomy, but none was due to a failed PCI. The primary end point of death, nonfatal reinfarction, or disabling stroke at 30 days was 8.5% in those transferred versus 5.0% in those treated with primary PCI without on-site cardiac surgery (P=0.27). The success of this approach depends not only on the availability of stents but also on the maintenance of high standards of care. For example, in order for the hospital to be part of the Air PAMI-No SOS registry, adherence to rigorous guidelines was mandated, including the following: (1) Experienced interventionalists who regularly perform elective PCI procedures at a surgical center, (2) experienced cardiac catheterization laboratory staff on a 24-hours-per-day, 7-days-per week call schedule, (3) a fully equipped catheterization laboratory with digital imaging, (4) in