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Multidisciplinary Standardized Care for Acute Aortic Dissection

2010; Lippincott Williams & Wilkins; Volume: 3; Issue: 4 Linguagem: Inglês

10.1161/circoutcomes.109.920140

1941-7705

Kevin M. Harris, Craig Strauss, Sue Duval, Barbara Unger, Timothy J. Kroshus, Subbarao Inampudi, Jonathan Cohen, Christopher Kapsner, Lori L. Boland, Frazier Eales, Eric Rohman, Quirino Orlandi, Thomas F. Flavin, Vibhu R. Kshettry, Kevin J. Graham, Alan T. Hirsch, Timothy D. Henry,

Cardiac Structural Anomalies and Repair

HomeCirculation: Cardiovascular Quality and OutcomesVol. 3, No. 4Multidisciplinary Standardized Care for Acute Aortic Dissection Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissionsDownload Articles + Supplements ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toSupplemental MaterialFree AccessResearch ArticlePDF/EPUBMultidisciplinary Standardized Care for Acute Aortic DissectionDesign and Initial Outcomes of a Regional Care Model Kevin M. Harris, Craig E. Strauss, Sue Duval, Barbara T. Unger, Timothy J. Kroshus, Subbarao Inampudi, Jonathan D. Cohen, Christopher Kapsner, Lori L. Boland, Frazier Eales, Eric Rohman, Quirino G. Orlandi, Thomas F. Flavin, Vibhu R. Kshettry, Kevin J. Graham, Alan T. Hirsch and Timothy D. Henry Kevin M. HarrisKevin M. Harris From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Craig E. StraussCraig E. Strauss From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Sue DuvalSue Duval From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Barbara T. UngerBarbara T. Unger From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Timothy J. KroshusTimothy J. Kroshus From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Subbarao InampudiSubbarao Inampudi From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Jonathan D. CohenJonathan D. Cohen From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Christopher KapsnerChristopher Kapsner From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Lori L. BolandLori L. Boland From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Frazier EalesFrazier Eales From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Eric RohmanEric Rohman From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Quirino G. OrlandiQuirino G. Orlandi From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Thomas F. FlavinThomas F. Flavin From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Vibhu R. KshettryVibhu R. Kshettry From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Kevin J. GrahamKevin J. Graham From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. , Alan T. HirschAlan T. Hirsch From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. and Timothy D. HenryTimothy D. Henry From the Minneapolis Heart Institute Foundation at Abbott-Northwestern Hospital (K.M.H., S.D., B.T.U., T.J.K., F.E., E.R., Q.G.O., T.F.F., V.R.K., K.J.G., T.D.H.); Division of Cardiology (C.E.S.) and Epidemiology and Community Health (S.D., A.T.H.), University of Minnesota; Consulting Radiology, Ltd (S.I.); Northwest Anesthesia, PA (J.D.C.); Emergency Care Consultants, PA (C.K.); Center for Healthcare Innovation, Allina Hospitals and Clinics (L.L.B.), Minneapolis, Minn. Originally published1 Jul 2010https://doi.org/10.1161/CIRCOUTCOMES.109.920140Circulation: Cardiovascular Quality and Outcomes. 2010;3:424–430"No physician can diagnose a condition he never thinks about."—Michael DeBakeyPatients with acute aortic dissection (AAD) have an in-hospital mortality of 26%, and for those patients with type A AAD, the mortality risk is 1% to 2% per hour until emergency surgical repair is performed.1,2 It is therefore critical that AAD be recognized promptly and that surgical care be provided expeditiously. Data from the International Registry of Acute Aortic Dissection (IRAD) indicate that the median time from emergency department (ED) presentation to definitive diagnosis of AAD is 4.3 hours, with an additional 4 hours between diagnosis and surgical intervention for type A patients.2,3 A portion of the delay to surgery is often the result of the patient's presenting to smaller community hospitals underequipped to manage emergent AAD. Transfer to high-volume aortic care centers with highly specialized facilities and expertise is routine, but even at such centers, current surgical mortality is 25%.4Goals and Vision of the ProgramIn an effort to address factors that delay AAD recognition and optimal management, a standardized, quality-improvement protocol for the regional treatment of AAD was developed and implemented with the goal of providing consistent, integrated, and coordinated care for patients with AAD throughout all phases of care. Modeled, in part, after a successful regional program for ST-segment elevation myocardial infarction,5, the specific aims of the program were to decrease the time from hospital arrival to diagnosis and treatment and to improve clinical outcomes for patients with AAD. A collaborative team designed program elements directed at (1) increasing awareness and knowledge of AAD among emergency care providers, (2) standardizing optimal care for AAD through the use of a formal protocol, (3) improving care coordination and communication across disciplines, and (4) providing feedback and quality improvement to treating clinicians. This report highlights key components of the protocol, the process of implementation, and initial clinical outcomes.MethodsLocal Challenges in ImplementationAn interdisciplinary committee (cardiologists, cardiovascular [CV] surgeons, vascular medicine and surgeons, cardiac anesthesiologists, radiologists, AAD program nurses, community and tertiary hospital ED physicians, and a CV administrator) worked to define an ideal AAD care pathway extending from rural hospital diagnosis to tertiary care hospital discharge, and the following areas were targeted for process improvement: (1) delayed initial diagnosis, (2) nonstandardized diagnostic testing and pharmacotherapy, (3) delays occurring between community hospital presentation and interhospital transfer, (4) delays between AAD center arrival and the initiation of surgical care, (5) delays in availability and preparation of blood products for transfusion, (6) inconsistent provision of intraoperative aortic imaging; and (7) inconsistent follow-up after discharge.Design of the InitiativeRegional NetworkThe Minneapolis Heart Institute at Abbott Northwestern Hospital (hereafter referred to as the AAD Center) is a tertiary hospital with existing relationships with a large number of rural and community hospitals (hereafter referred to as community) throughout the upper Midwest. The current program involves 32 community hospitals in Minnesota, North Dakota, and western Wisconsin that received program-related education, protocols, and toolkits and referred patients to the AAD Center for advanced AAD care. The majority of the community hospitals were part of a defined network of facilities ("in-network") that receive ongoing CV continuing medical education through the regional level 1 ST-segment elevation myocardial infarction program.5 Six additional hospitals that participate less formally in these regional CV programs ("out-of-network") also referred AAD patients during the study period.Provider EducationSince the inception of the AAD program in 2005, >60 educational AAD talks and training sessions have been offered to local EDs, at primary care and emergency medicine continuing education conferences, and at regional medical transport bases. A cardiologist or CV surgeon and the program director visited each hospital in the regional network and conducted training sessions (please see online data supplement for Appendix). In addition to dissemination of the protocol and tools, program education also includes site-specific feedback to participating referring physicians, hospitals, and transport teams after each AAD event.Implementation of the Initiative: Standardized AAD ProtocolInitial Management at Community HospitalsStandardized order sets for the initial management of AAD, including pharmacotherapy and diagnostic guidelines and AAD Center contact phone numbers, were provided to community hospitals. On confirmation of an AAD, the community hospital staff alerts the transport service and the AAD Center and administers recommended medications (labetalol or esmolol) to achieve desired parameters (systolic blood pressure 100 to 120 mm Hg and heart rate 60 to 80 beats/min), provided that the patient is not hypotensive or bradycardic6 (Figure).Download figureDownload PowerPointFigure. Flow diagram outlining the clinical pathway of patients with suspected or confirmed AAD.Chest computed tomography (CT) was selected as the primary diagnostic imaging method.7,8 A standardized imaging protocol applied across participating hospitals eliminates the need for repeated testing, promotes efficient activation of the surgical team, and thereby reduces time to treatment, radiation exposure, and cost. All CT scans are obtained, transmitted, and interpreted on a priority basis. Initial images are obtained without contrast to exclude intramural hematoma, followed by multislice spiral CT scans of the chest and abdomen with a 2.5-mm slice thickness, with contrast. In 45% of the participating community hospitals (n=14), CT images are transmitted to the tertiary hospital radiologist via the Picture Archiving and Communication Systems network for confirmation before patient transfer. Where this capability does not exist, the image is interpreted locally and saved on a disk that is transported with the patient. To ensure consistency of image reporting, a standardized report template containing a schematic diagram is used to illustrate and record key aspects of the dissection.Interhospital Coordination and TransportOn confirmation or suspicion of an AAD at a community hospital, 1 phone call activates the protocol. A nurse coordinator at the AAD Center is assigned to assist with transfer arrangements and receipt of the patient. A cardiologist and CV surgeon review the case with the ED or transferring physician, and cases are designated as confirmed or suspected. Suspected AAD cases are those with suggestive but not definitive imaging results at the community hospital. All major ground and air medical-transport service providers in the region participated in AAD protocol training and education. Standardized medication guidelines are used to maintain hemodynamic goals en route, and transport personnel provide an estimated arrival time as well as a "15-minute out" page to AAD Center personnel. The AAD Center radiology department is informed of the pending patient arrival time, so that transported diagnostic images can be expeditiously interpreted on arrival.AAD Center EDThe AAD Center ED serves as the stabilization site. A cardiologist, available in-house 24 hours, directs initial patient management in the ED, with the CV surgeon assuming leadership of the AAD team once the diagnosis is confirmed. An electronic AAD toolkit, which includes estimated transport times, community hospital contact information, and guidelines for initial management, is available. Computer stations in the ED were upgraded to enable immediate review of CT scans. In cases of suspected AAD, where images from the community hospital are unavailable or inconclusive, definitive imaging is performed immediately on arrival.In confirmed type A cases, the CV surgeon determines whether the patient is a surgical candidate, initiates the AAD surgical order set in the electronic health record, and pages the multidisciplinary AAD team, including the CV operating room (CVOR). The OR order set includes preoperative antibiotics and antihypertensive medications, as well as a priority request from the blood bank of red blood cells (4 units of crossmatched or O-negative red blood cells), 4 units of fresh frozen plasma, and 2 units of platelets. Coronary angiography is not performed routinely. The AAD team anesthesiologist performs an assessment of the patient and transports him/her to the CVOR.Surgical ManagementPatients with AAD are classified as type A (involving the ascending aorta) or type B (confined to the descending aorta) in accordance with conventional criteria. Consistent with IRAD, patients with aortic intramural hematoma were included in the analyses, whereas patients with giant penetrating ulcers were excluded. An aortic intramural hematoma involving the ascending aorta is treated with immediate surgical intervention, similar to a type A aortic dissection, whereas type B aortic dissections (or intramural hematomas) are treated initially with medical therapy unless there are indications for emergency surgical intervention.9A dedicated CVOR is readily available and prepared when a confirmatory page is received. Appropriate venous access is established, and arterial and central lines are placed. Once the patient is anesthetized, intraoperative transesophageal echocardiography (TEE) is performed. The TEE confirms the diagnosis, delineates aortic valve involvement, and provides a means of intraoperative monitoring and planning.10 The blood bank is notified of any potential need for additional blood products, including platelets, cryoprecipitate, and factor VII. A consistent surgical management approach for the repair of type A AADs with techniques that have been well described11,12 is promoted by the dedicated group of 4 CV surgeons who share call and have performed all emergent aortic repairs at the hospital in recent years. Although every attempt is made to spare the valve by using Dacron interposition grafts, composite grafts are used when needed. Circulatory arrest is used routinely when arch repair is performed and otherwise at the discretion of the surgeon. An open aortic anastomotic technique for reconstruction of the native aortic distal anastomotic site is preferred. Intraoperative TEE continues after separation from cardiopulmonary bypass to aid in assessment of the repair and aortic valve function.Discharge and Follow-UpAt discharge, all patients are scheduled for a 3-month, outpatient follow-up visit at a dedicated aortic care clinic. Follow-up imaging is scheduled in accordance with consensus recommendations.6 Imaging is preferentially done with magnetic resonance imaging. Echocardiograms are conducted before discharge and annually in patients with interposition grafts. The AAD team communicates the follow-up plan with the patient's primary care physician, and a patient information sheet regarding AADs and the importance of follow-up is reviewed with the patient.Program EvaluationCase Ascertainment and DefinitionsOutcomes were assessed before (January 1, 2003 to July 31, 2005) and after (August 1, 2005 to September 1, 2009) protocol initiation. Cases were identified either retrospectively through hospital discharge diagnosis codes or prospectively after protocol initiation. The study was reviewed and approved by the Abbott Northwestern Hospital institutional review board. All patients were included in the results of the quality-assurance program unless they signed "no" to research process. In addition, patients who survived signed a consent for long-term follow-up. A comprehensive database is used to collect all relevant data abstracted by specially trained clinical research assistants and is reviewed for accuracy by the lead cardiologist (K.M.H.). Location of initial presentation was categorized as community or tertiary (AAD Center). Community hospitals were further designated as in-network and out-of-network, as noted earlier.The outcomes assessed were (1) time from presentation to confirmed diagnosis for all AAD patients and for type A patients undergoing surgical treatment, (2) time to OR, (3) use of β-blockers on arrival and at discharge, (4) use of intraoperative TEE, and (5) in-hospital all-cause mortality. Time to OR (minutes) was defined for surgically managed type A patients and represented either the time from confirmed diagnosis to the OR (patients presenting to the AAD Center) or the time from the AAD Center arrival to the OR (patients presenting at community hospitals).Statistical AnalysisBetween January 1, 2003 and September 1, 2009, 107 cases of AAD were treated at the AAD Center. The analysis includes 101 (30 preprotocol, 71 postprotocol) cases in the analyses (5 patients who did not consent to research and 1 with iatrogenic dissection were excluded). Patients who did not present directly to an ED or who had a dissection discovered incidentally by imaging were excluded from the analyses of time from presentation to diagnosis (n=4) and time to OR (n=3). χ2 or Fisher exact test was used to assess the statistical significance of categorical variables, and t tests were used to test for differences in continuous variables before and after protocol implementation. Time segment values (in minutes) were transformed to natural logarithms (time-segment values) to more closely approximate a normal distribution and are reported as median and interquartile range (25th and 75th percentiles). t Tests were performed on logarithmic (time) values to test for differences in times before and after protocol. A value of P≤0.05 was considered statistically significant, and all reported probability values are 2 sided. Statistical calculations were done in Stata 10.0 (Stata Corp, College Station, Tex).ResultsSuccess of the InitiativeThe mean patient age was 64 years and 55% were men (Table 1). The majority were type A dissections (68%) who were transferred from community hospitals (76%). Seven cases (2 preprotocol, 5 postprotocol) of type A dissection were managed medically because of comorbid conditions, often in the very elderly (including bowel infarction, severe chronic obstructive pulmonary disease, shock, unresponsiveness, or multisystem organ failure) for whom the option of surgery was considered but the surgeon and patient/family opted to pursue a hospice approach. An additional 2 type A dissection patients died before surgery could be performed (both in the postprotocol group). The postprotocol type A patients had more significant comorbid complications, including hypotension, neurologic deficits, cardiac tamponade, and myocardial ischemia (data not shown). Two postprotocol patients with type B dissections underwent endovascular intervention. CT scans were performed as the initial imaging modality in 86% of cases. More than 1 imaging study was required for confirmation of the diagnosis in 47% of cases. Among the 101 cases, the diagnostic imaging modality was CT scan, aortogram, magnetic resonance imaging, or TEE in 90%, 4%, 3%, and 3%, respectively.Table 1. Characteristics of Patients With AADCharacteristicAll (N=101)Before Protocol (n=30)After Protocol (n=71)P ValueAge, y64±1764±1864±170.89Male56 (55)19 (63)37 (52)0.30Transfer*77 (76)22 (73)55 (77)0.66Type A dissection69 (68)22 (73)47 (66)0.48 Type A, surgical60 (59)20 (67)40 (56)0.33Type B dissection32 (32)8 (27)24 (34)0.48Medical history Hypertension76 (75)24 (80)52 (73)0.47 Diabetes5 (5)2 (7)3 (4)0.63 Marfan syndrome3 (3)1 (3)2 (3)1.00 Bicuspid aortic valve7 (7)5 (17)2 (3)0.02 Prior cardiac surgery1 (1)0 (0)1 (1)1.00Chest pain at presentation73 (72)23 (77)50 (70)0.52Values expressed as mean±SD or No. (%).*Patient initially presented at a community hospital and was transferred to a tertiary facility.Table 2 presents a comparison of the time from initial presentation to confirmation of the AAD diagnosis before and after protocol implementation. Overall, there was a 43% reduction (median, 279 to160 minutes; P=0.014) in the time to diagnosis, driven primarily by a significant improvement among those patients initially evaluated at community hospitals and those with type B dissection. In patients transferred from community hospitals to the AAD Center, the median time from initial presentation to confirmed diagnosis was reduced by almost 4.5 hours. In the small number of patients presenting directly to the AAD Center, the time from presentation to diagnosis increased slightly but remained dramatically shorter than for patients initially presenting at community hospitals.Table 2. Time From Presentation to Confirmed Diagnosis of AAD, Before and After Protocol Implementation, by Type of Dissection and Hospital of Initial PresentationCharacteristicBefore ProtocolAfter ProtocolP ValuenTimenTimeType A and B All hospitals30279(109, 945)67160(82, 288)0.014 Tertiary884(70, 134)13124(84, 160)0.733 Community (all)22437(233, 1290)54175(82, 379)0.002 Community (in-network only)22437(233, 1290)45168(82, 379)0.003Type A only All hospitals22246(96, 838)44176(101, 405)0.388 Tertiary671(69, 96)9134(84, 162)0.403 Community (all)16437(212, 1020)35196(101, 452)0.115 Community (in-network only)16437(212, 1020)27187(101, 873)0.176Type B only All hospitals8331(134, 2340)23110(74, 180)0.0023 Tertiary2134(127, 140)497(56, 120)0.36 Community (all)6883(303, 3272)19120(74, 201)0.0015Time values (in minutes) are expressed as median (25th percentile, 75th percentile). Four patients were excluded from these analyses owing to unclear presentation time.Among type A AAD patients undergoing surgical intervention, the median time from presentation to the OR decreased 30% after implementation of the protocol, driven by the reduction in community hospital values (median, 728 to 366; P=0.039;Table 3). Patients presenting at in-network community hospitals appeared to benefit most, with a 57% reduction in the median delay between presentation and surgical intervention. Median time (within the AAD Center) from diagnosis to OR in type A AAD patients decreased by 55% after protocol implementation (median, 113 to 51; P=0.006;Table 3), and despite an emphasis on reducing critical time segments, there were no instances of surgical intervention occurring as the result of a false-positive diagnosis.Table 3. Time to OR in Surgically Managed Type A AAD Patients, Before and After Protocol Implementation, by Hospital of Initial PresentationVariableBefore ProtocolAfter ProtocolP ValuenTimenTimeTime from initial presentation to OR All hospitals20482(252, 1137)37338(223, 586)0.188 Tertiary5192(136, 219)7233(165, 295)0.421 Community (all)15728(369, 1487)30366(229, 784)0.039 Community (in-network only)15728(369, 1487)22316(216, 1099)0.056Time from diagnosis to OR*20113(51, 174)3751(34, 98)0.006Values are expressed as median (25th percentile, 75th percentile). Three type A surgically managed patients treated after protocol implementation were excluded from these analyses owing to unclear presentation time.*Within tertiary facility.After program implementation, the percentage of nonhypotensive patients receiving β-blockers on arrival at the AAD Center increased dramatically to 97% (Table 4). In addition, 100% of AAD patients were prescribed β-blockers at discharge in the postprotocol period, compared with only 85% in the preprotocol period. Intraoperative TEE was used in nearly all types of A AAD repair procedures. The in-hospital mortality for type A cases undergoing surgical repair demonstrated a trend toward reduction (43% lower) compared with the mortality observed before protocol implementation. Among those patients who survived to hospital discharge, the rate of follow-up care in the outpatient setting within 6 months of the index event was 75% before protocol and 85% after protocol (P=NS).Table 4. β-Blocker Use and Use of Intraoperative Imaging in AAD Before and After Protocol Implementationβ-Blocker Use*Before ProtocolAfter ProtocolP ValueAll AADs On arrival (All)14/22 (64)